@article{faeli_montoya_gabr_2024, title={Development of a reactive transport model for microbial induced calcium carbonate precipitation in unsaturated conditions}, volume={3}, ISSN={["1208-6010"]}, DOI={10.1139/cgj-2022-06771}, journal={CANADIAN GEOTECHNICAL JOURNAL}, author={Faeli, Zahra and Montoya, Brina M. and Gabr, Mohammed A.}, year={2024}, month={Mar} }
 @article{kim_shahriar_lee_gabr_2024, title={Interpretable machine learning scheme for predicting bridge pier scour depth}, url={https://doi.org/10.1016/j.compgeo.2024.106302}, DOI={10.1016/j.compgeo.2024.106302}, abstractNote={Predicting scour depth around bridge piers is challenging due to the involvement of various uncertain factors and complex processes, making it difficult to obtain accurate results using traditional deterministic models. Recently, nonlinear analysis and prediction using machine learning (ML) techniques that glean statistical structures from input/output data have received substantial attention. With the use of ML, however, interpretation becomes difficult with increased complexity and diversity of the analysis parameters. The study herein proposes a local scour depth prediction model around piers using interpretable ML. A scour depth prediction model was constructed using the state-of-the-art eXtreme Gradient Boositng (XGB) model, and Shapley additive explanations (SHAP) based on the cooperative game theory. The ML model demonstrated excellent prediction accuracy (R2: 0.75, RMSE: 0.23) compared with existing empirical formulas used for assessment of pier scour. Model analysis results demonstrated that for each input variable, the distribution of SHAP values for scour depth is consistent with the general theoretical knowledge about the factors influencing scour depth, suggesting that the predictions of the XGB model are reasonable. Considering accuracy and conservatism, design recommendations using two statistical parameters: mean absolute percentage error (MAPE) and the percentage of predicted scour depth exceeding measured scour depth, referred to as the "level of conservatism" were proposed as a means of providing the flexibility of including a target level of accuracy and conservatism in the computed scour depth.}, journal={Computers and Geotechnics}, author={Kim, Taeyoon and Shahriar, Azmayeen R. and Lee, Woo-Dong and Gabr, Mohammed A.}, year={2024}, month={Jun} }
 @article{vo_jamaleddin_gabr_borden_2024, title={Natural Frequency and Foundation Damping of Colocated and Hybrid Systems Sharing Wind Turbine Monopiles under Operational Conditions}, volume={24}, ISSN={["1943-5622"]}, url={https://doi.org/10.1061/IJGNAI.GMENG-8469}, DOI={10.1061/IJGNAI.GMENG-8469}, number={1}, journal={INTERNATIONAL JOURNAL OF GEOMECHANICS}, author={Vo, Long and Jamaleddin, Neda and Gabr, Mohammed and Borden, Roy}, year={2024}, month={Jan} }
 @article{jamaleddin_gabr_borden_argall_lasser_2024, title={Numerical study on micropile group behavior supporting fixed bottom marine hydrokinetic devices in sandy seabed}, volume={293}, ISSN={["1873-5258"]}, url={https://doi.org/10.1016/j.oceaneng.2023.116614}, DOI={10.1016/j.oceaneng.2023.116614}, abstractNote={This study aimed to investigate the behavior of micropile groups supporting fixed bottom marine hydrokinetic (MHK) devices in sandy seabed. A parametric study using PLAXIS 3D was conducted to examine the influence of key design parameters on the lateral load and moment capacity of the micropile group. The parameters considered were micropile diameter, spacing, micropile cap size, number of micropiles, micropile-soil interface properties, and sand packing state. Using the parametric study results, fitting regression techniques were employed to derive equations for predicting the MR (moment resistance in the absence of lateral load) and HR (Lateral resistance in the absence of moment loading), while meeting ultimate limit state (ULS). The equations were formulated based on soil relative density (DR), micropile group polar moment of inertia (J), and an interface reduction factor (Rint). A linear failure envelope is proposed in the Moment-Horizontal (M-H) load space by connecting MR and HR. The proposed framework was then applied to assess the load utilization ratio for various configurations, focusing on a load example of anchoring a 1 MW marine tidal turbine. The results of the study provide insights into the behavior and design of micropile groups supporting fixed bottom MHK devices in sandy seabed.}, journal={OCEAN ENGINEERING}, author={Jamaleddin, Neda and Gabr, Mohammed and Borden, Roy and Argall, Richard and Lasser, Donald}, year={2024}, month={Feb} }
 @article{cui_amani_gabr_kumari_ahmed_ozcan_horri_bhattacharya_2024, title={Synergistic Hybrid Marine Renewable Energy Harvest System}, volume={17}, ISSN={["1996-1073"]}, url={http://dx.doi.org/10.3390/en17051240}, DOI={10.3390/en17051240}, abstractNote={This paper proposes a novel hybrid marine renewable energy-harvesting system to increase energy production, reduce levelized costs of energy and promote renewable marine energy. Firstly, various marine renewable energy resources and state-of-art technologies for energy exploitation and storage were reviewed. The site selection criteria for each energy-harvesting approach were identified, and a scoring matrix for site selection was proposed to screen suitable locations for the hybrid system. The Triton Knoll wind farm was used to demonstrate the effectiveness of the scoring matrix. An integrated energy system was designed, and FE modeling was performed to assess the effects of additional energy devices on the structural stability of the main wind turbine structure. It has been proven that the additional energy structures have a negligible influence on foundation/structure deflection (<1%) and increased system natural frequency by 6%; thus, they have a minimum influence on the original wind system but increased energy yield.}, number={5}, journal={ENERGIES}, author={Cui, Liang and Amani, Sadra and Gabr, Mohammed and Kumari, Wanniarachchige Gnamani Pabasara and Ahmed, Aziz and Ozcan, Hasan and Horri, Bahman Amini and Bhattacharya, Subhamoy}, year={2024}, month={Mar} }
 @misc{rafiei_gabr_rahman_2023, title={Analysis of Wave-Driven Progressive Buildup of Excess Pore Water Pressure in Sands Supporting Marine Hydrokinetic Devices}, url={http://dx.doi.org/10.4043/32639-ms}, DOI={10.4043/32639-ms}, abstractNote={Abstract}, journal={Day 1 Mon, May 01, 2023}, publisher={OTC}, author={Rafiei, Amin and Gabr, M. A. and Rahman, M. S.}, year={2023}, month={Apr} }
 @article{faeli_montoya_gabr_2023, title={Development of a Reactive Transport Model for Microbial Induced Calcium Carbonate Precipitation in Unsaturated Conditions}, volume={61}, ISSN={0008-3674 1208-6010}, url={http://dx.doi.org/10.1139/cgj-2022-0677}, DOI={10.1139/cgj-2022-0677}, abstractNote={ Microbial induced calcium carbonate precipitation (MICP) offers a sustainable technique to improve geologic properties of soils in engineering structures. The applications encompass improved soil strength, scour mitigation, fracture sealing, and in situ contaminant immobilization. Previous studies have presented fundamental processes and implementation in lab- and field-scale. Most of these studies were examined in saturated conditions despite many MICP applications including those in coastal and riverside areas which will likely take place under unsaturated conditions. The study herein investigated the effect of soil water retention curve (SWRC) parameters and attachment coefficient ( Kat ) on CaCO3 precipitation in sand. Using numerical analyses, a continuum model was developed in which unsaturated flow and transport were coupled with biological and chemical reactions in variably saturated conditions. Predictive modeling results compare mass percentage of calcium carbonate resulting from MICP at degrees of soil water saturations of 20%, 40%, 80%, and 100% in sandy soil media. The results indicate the bacteria attachment coefficient increases by a factor of 3 as the degree of saturation is decreased from 100% to 20%, as the higher suctions at lower saturation levels improve bacteria fixation. The drying branch of SWRC versus wetting front yields higher CaCO3 for identical MICP treatment. Numerical results show the trend in hydraulic conductivity with increasing cementation level. }, number={4}, journal={Canadian Geotechnical Journal}, publisher={Canadian Science Publishing}, author={Faeli, Zahra and Montoya, Brina M. and Gabr, Mohammed}, year={2023}, month={Aug}, pages={827–835} }
 @article{almuaythir_gabr_pour-ghaz_2023, title={Efficacy of Permeable Reactive Barriers in Mitigating Tetrachloroethene Ingress into Highway Drainage Concrete Pipe in Saturated Media}, volume={14}, ISSN={["1949-1204"]}, url={https://doi.org/10.1061/JPSEA2.PSENG-1417}, DOI={10.1061/JPSEA2.PSENG-1417}, abstractNote={Work herein is focused on evaluating factors affecting tetrachloroethene (PCE) contaminant ingress into the subsurface concrete pipe embedded in the saturated soil profile and assessing the efficacy of permeable reactive barriers (PRB) in mitigating PCE concentration. A three-dimensional groundwater flow and solute transport numerical model is established using MODFLOW paired with reactive transport (RT3D) software, in which the model is developed using a finite-difference numerical scheme. The analyses parameters are developed from data for a site in Wilson, North Carolina, at which subsurface chlorinated organic solvents from a dry-cleaning facility occurred in the presence of subsurface highway concrete drainage pipe. Modeling results after 10 years of simulation period indicated that the natural attenuation process taking place in the native soils with coefficients of KPCE=0.00019 d−1, and 0.0033 d−1 reduced the PCE concentrations breaking through the concrete pipe by 30.7% and 34.1%, respectively. On the other hand, with a greater percent of the soil sorption as manifested by organic carbon content, the PCE concentration breaking through the pipe increased by 137% for the same simulation period as a result of the prolonged presence of PCE concentration within the pipe trench. The hydraulic conductivity of the PRB (kPRB) modestly affects the level of PCE breaking through the pipe, while the increase in thickness of the PRB was found to be the most effective in decreasing the level of PCE ingress into the pipe.}, number={2}, journal={JOURNAL OF PIPELINE SYSTEMS ENGINEERING AND PRACTICE}, author={Almuaythir, Sultan and Gabr, Mohammed and Pour-Ghaz, Mohammad}, year={2023}, month={May} }
 @article{faeli_montoya_gabr_2023, title={Elucidating factors governing MICP biogeochemical processes at macro-scale: A reactive transport model development}, volume={160}, ISSN={0266-352X}, url={http://dx.doi.org/10.1016/j.compgeo.2023.105514}, DOI={10.1016/j.compgeo.2023.105514}, abstractNote={Microbial Induced Calcium Carbonate Precipitation (MICP) influenced by biofilm metabolism in the subsurface can be exploited for a variety of engineered applications encompassing geotechnical ground improvement, environmental bioremediation, and hydraulic barriers. A reactive transport model was developed to determine the effects of controlling factors in terms of treatment protocols and experimental methods. Six column tests were calibrated and a range for the key parameters was determined. Fifteen key parameters of MICP reactive transport model were assessed in four categories (microbial activity and attachment, sample preparation, treatment protocol, and experiment dimensions). The results emphasized the effects of three main factors of microbial activity, microbial attachment process, and number of treatment (among all 15 assessed parameters) on the calcium carbonate (CaCO3) precipitation content and distribution. An increase in specific ureolysis rate (Ku) and attachment rate coefficient (Kat) by two orders of magnitude improves average CaCO3 by up to 13% and 6%, respectively with non-uniformity (COV) increase of 16%. Higher flow rates and solution concentrations contribute to more uniform CaCO3 distribution. The constant attachment rate model is useful to yield the CaCO3 precipitation profiles but more accurate models are needed to capture exact distribution. Post-treatment hydraulic conductivity, porosity and attached biomass were assessed.}, journal={Computers and Geotechnics}, publisher={Elsevier BV}, author={Faeli, Zahra and Montoya, Brina M. and Gabr, Mohammed A.}, year={2023}, month={Aug}, pages={105514} }
 @article{shahriar_gabr_montoya_ortiz_2023, title={Estimating live-bed local scour around bridge piers in cohesionless sediments: applicability and bias of selected models}, volume={60}, ISSN={["1208-6010"]}, url={http://dx.doi.org/10.1139/cgj-2022-0122}, DOI={10.1139/cgj-2022-0122}, abstractNote={ To design the foundation system of waterway bridges, Load and Resistance Factor Design guidelines suggest use of deterministic scour depth prediction models. Understanding the inherent bias of deterministic scour depth prediction models will advance the development of reliability index-based foundation design regime. Four bridge scour depth prediction models were assessed in terms of two statistical parameters, termed herein mean absolute percentage error (MAPE), and conservatism, percentage of cases the predicted scour depth exceeded the measured scour depth. Live-bed laboratory and field scour depth databases were used in analyses to quantify model scatter by comparatively assessing the computed scour depth versus measured data. For live-bed laboratory data, values of MAPE ranged from 23.5% to 59.8%, whereas conservatism ranged from 28.4% to 97.8%. For live-bed field data, conservatism varied from 93.3% to 95.1%, while MAPE ranged from 205.6% to 319%. Statistical models were applied to ascertain the biasness of the four deterministic models. Accuracy and conservatism of a given model were consequently adjusted through proposed modification factors. The proposed approach allows for the selection of a suitable modification factor to satisfy a target probability of deceedance or a target conservatism. }, number={4}, journal={CANADIAN GEOTECHNICAL JOURNAL}, publisher={Canadian Science Publishing}, author={Shahriar, Azmayeen R. and Gabr, Mohammed A. and Montoya, Brina M. and Ortiz, Alejandra C.}, year={2023}, month={Apr}, pages={471–487} }
 @article{rafiei_rahman_gabr_2023, title={Evaluation of wave-induced instability of nearly saturated sandy slopes under partially undrained condition: A case study of landslide in Fraser River delta front}, volume={159}, ISSN={["1873-7633"]}, DOI={10.1016/j.compgeo.2023.105496}, abstractNote={A significant amount of Methane gas in soil deposits at Fraser River Delta (FRD), Canada, was identified as it adversely impacted the stability of the sloping seabed in the area under waves and tides. In this study, an integrated FEM model is utilized to investigate the instability of FRD front due to 1985 storm waves. Despite earlier studies that focused only on the role of residual pore pressure reached at late wave cycles in inducing the slide of FRD front (using empirical correlations), the transient response of sediments at early wave cycles is considered herein. The effect of coupled-flow-and-deformation processes within the sediments on the extent of the sliding plane is considered. For wave-seabed interaction modeling, Biot's poroelasticity and linear wave theory are employed to represent the fluid and seabed domains, respectively. The slide evaluation of the sloping seabed is conducted using Strength Reduction Technique with Mohr-Coulomb failure criterion. The results indicate that the storm waves cause a shallow slide within the slope, and the proximity of the unsaturated layer to mudline exacerbated the instability condition. Moreover, instantaneous liquefaction zones are found to emerge away from the slope; thus, they may not lead to an exacerbated sliding of the slope.}, journal={COMPUTERS AND GEOTECHNICS}, author={Rafiei, Amin and Rahman, M. S. and Gabr, M. A.}, year={2023}, month={Jul} }
 @article{shahriar_gabr_montoya_ortiz_2023, title={Framework for a reliability-based analysis of local scour and its effect on pile response in clay}, volume={153}, ISSN={0266-352X}, url={http://dx.doi.org/10.1016/j.compgeo.2022.105093}, DOI={10.1016/j.compgeo.2022.105093}, abstractNote={The analyses of axial and lateral capacity of a pile are significantly dependent on the appropriate estimation of scour depth, while the scour depth estimation procedure is uncertain due to the hydraulic, hydrologic, and geotechnical parameters uncertainty. Work herein is focused on developing a framework for reliability-based pier scour assessment methodology and demonstrate its integration with the concept of Load and Resistance Factor Design (LRFD) approach. Scour factors are proposed based on reliability level ( β ) and the associated probability of deceedance (POD). Three example applications of axially and laterally loaded pile design approach while including scour factor in the LRFD framework are demonstrated. Based on axial pile capacity analysis, the increase of pile length when the β -based scour assessment is used with the soil resistance factors, was estimated to be 26.5–29.6 % higher compared to using the deterministic scour with soil resistance factor. In the case of lateral pile response analysis, as β is increased from 2.0 to 3.0, the lateral pile head deflection increased by 46–132 % compared to the deterministically-estimated scour depth case. To obtain β = 3.0 for the considered example while maintaining the pile length unchanged, the pile diameter needed to be increased by 35.7 % compared to the base case pile’s diameter.}, journal={Computers and Geotechnics}, publisher={Elsevier BV}, author={Shahriar, Azmayeen R. and Gabr, Mohammed A. and Montoya, Brina M. and Ortiz, Alejandra C.}, year={2023}, month={Jan}, pages={105093} }
 @article{shahriar_gabr_montoya_ortiz_2023, title={Local scour around bridge abutments: Assessment of accuracy and conservatism}, volume={619}, ISSN={["1879-2707"]}, url={https://doi.org/10.1016/j.jhydrol.2023.129280}, DOI={10.1016/j.jhydrol.2023.129280}, abstractNote={More than 80 percent of the bridges in the United States are built over waterways. The support systems of the structures crossing waterways are subjected to scour during their service life owing to the flowing water-induced bed shear stresses, resulting in scour. Work herein is focused on characterizing the error associated with three abutment scour prediction models included in the Hydraulic Engineering Circular No. 18. An abutment scour database is utilized to quantify the predicted versus the measured scour depth relationship. Abutment scour prediction models are assessed in terms of two statistical parameters, termed herein Mean Absolute Percentage Error (MAPE, as a measure of accuracy of the prediction), and Level of conservatism, (defined as percentage of cases for which the predicted scour exceeded the measured scour.) For scour associated with vertical wall and spill through abutments, responses to long abutment, and intermediate abutment are examined separately. For vertical wall abutments, conservatism ranged from 4.76% to 100%, and MAPE ranged from 44% to 201%. For spill through abutments, conservatism ranged from 0% to 100%, and MAPE ranged from 10.3% to 347%. Comprehension of the accuracy and conservatism of the deterministic models considered herein contributes to understanding the limitation of the scour depth prediction models.}, journal={JOURNAL OF HYDROLOGY}, author={Shahriar, Azmayeen R. and Gabr, Mohammed A. and Montoya, Brina M. and Ortiz, Alejandra C.}, year={2023}, month={Apr} }
 @article{faeli_montoya_gabr_2023, title={Various Bacterial Attachment Functions and Modeling of Biomass Distribution in MICP Implementations}, volume={149}, ISSN={["1943-5606"]}, url={https://doi.org/10.1061/JGGEFK.GTENG-10812}, DOI={10.1061/JGGEFK.GTENG-10812}, abstractNote={Microbial induced calcium carbonate precipitation (MICP) offers a robust technique to improve strength and stiffness properties of subsurface soils supporting infrastructures. Several unknown factors, including the MICP reactive transport parameters, however, limit the ability to predict spatial distribution of calcium carbonate (CaCO3) precipitation within a subsurface area and with depth. As it was shown that calcium carbonate distribution is highly affected by biomass profiles in subdomains, five bacteria attachment models (constant-rate, power-law, exponential, gamma distribution, and "cstr based on colloid attachment theory") were calibrated here using data from both small- and large-scale testing programs. Out of the five models, colloid attachment theory with modified velocity and straining terms was shown to be the most promising approach in yielding the most fitted CaCO3 distribution compared with the experimental data. A new parameter, cstr, was incorporated to modify straining and the constraint peak value of biomass attachment due to straining at distances larger than a 0.14×sample size. Using the results from the numerical simulations, relationships were developed for velocity and straining coefficients of "the cstr based on colloid attachment theory" (hereafter "colloid attachment cstr") as a function of bacteria size, soil particle size, sample size, volume of injected bacteria, and soil pore volume.}, number={9}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, author={Faeli, Zahra and Montoya, Brina M. and Gabr, Mohammed A.}, year={2023}, month={Sep} }
 @article{faeli_hosseini_gabr_pour-ghaz_2022, title={A new monitoring approach for sustainability assessment of subsurface utilities gasket materials against gasoline and chlorinated solvents: Field evaluation and model development}, volume={323}, ISSN={0301-4797}, url={http://dx.doi.org/10.1016/j.jenvman.2022.116217}, DOI={10.1016/j.jenvman.2022.116217}, abstractNote={Once installed, underground concrete pipes with rubber gaskets might be exposed to contaminated soil and groundwater. A pipe material monitoring capsule (PMMC) has been developed to evaluate volatile organic compounds (VOCs) breaking through three types of pipe gaskets; Neoprene, Buna-N, and Viton. The PMMCs were deployed in three contaminated sites: two with gasoline and one with chlorinated solvent (CS). A 3-D field-domain numerical model has been developed for each site to calibrate equivalent hydraulic parameters of each gasket material (ke, D) against benzene and PCE diffusion. The calibrated parameters were then used to compute the concentrations as well as rate of breakthrough of the two study contaminants. A protocol was developed for installing/retrieval of PMMCs to monitor PCE and benzene mass breaking through the gasket material with time. Employing PMMC, benzene concentrations breaking through the Neoprene and Buna-N after 4 months were approximately 70% and 60% respectively of the monitoring wells concentration. The corresponding value for PCE breakthrough after 4 months was 60% for both the Neoprene and Buna-N. Both gasket materials of Neoprene and Buna-N yielded similar performances, including higher rate of contaminant breakthrough compared to Viton. A nonlinear relationship of mass breaking through the gaskets of benzene and PCE with time was discerned from the modeling and field data.}, journal={Journal of Environmental Management}, publisher={Elsevier BV}, author={Faeli, Zahra and Hosseini, Payam and Gabr, Mohammed A. and Pour-Ghaz, Mohammad}, year={2022}, month={Dec}, pages={116217} }
 @article{hosseini_mcelroy_knappe_gabr_pour-ghaz_2022, title={Diffusion of benzene and tetrachloroethylene through saturated cement paste}, volume={329}, ISSN={0950-0618}, url={http://dx.doi.org/10.1016/j.conbuildmat.2022.127196}, DOI={10.1016/j.conbuildmat.2022.127196}, abstractNote={Diffusion of highly volatile organic compounds (VOCs) through buried concrete infrastructure components, such as pipes and culverts, can occur if these components come in contact with contaminated groundwater or soil. Among various VOCs, benzene and tetrachloroethylene (PCE), are the most common contaminants. This paper aims at measuring the effective diffusion coefficients of benzene and PCE in cement paste. The free diffusion coefficients of VOCs in simulated pore solution were also measured and used in empirical models. Results show that VOCs diffusion coefficients decreased with decreasing w/c because of reduced porosity and increased tortuosity of the pore network as well as increased ionic strength of the pore solution. The increased ionic strength of the pore solution reduced the solubility limit of VOCs in the pore solution and decreased the free diffusion coefficient of VOCs in the pore solution. Also, among all models, phenomenological model provided the most accurate estimates.}, journal={Construction and Building Materials}, publisher={Elsevier BV}, author={Hosseini, Payam and McElroy, Amie and Knappe, Detlef R.U. and Gabr, Mohammed and Pour-Ghaz, Mohammad}, year={2022}, month={Apr}, pages={127196} }
 @article{jadid_montoya_gabr_2022, title={Framework for the Development of Strain-Based Ultimate Performance Limit State Criterion for the Stability of Earthen Embankments}, volume={148}, ISSN={["1943-5606"]}, url={https://doi.org/10.1061/(ASCE)GT.1943-5606.0002754}, DOI={10.1061/(ASCE)GT.1943-5606.0002754}, abstractNote={Repeated rapid drawdown (RDD) and rapid rise in water level during extreme events lead to the progressive development of plastic strain zones within the earth embankments with subtle, rather than obvious, visible signs of distress. The traditional approach within the framework of limit equilibrium does not account for accumulated permanent deformation with repeated hydraulic loading. Work presented herein is focused on quantifying the level of deviatoric strain, in terms of key surface deformation and distress level of earth embankment slopes, with repeated hydraulic loading. A simple linear relationship between the deviatoric strain and surface deformation at the toe of the slip surface is proposed as a function of the geometry of the slope for rotational sliding. This relationship is applied using the stress-strain data obtained from conventional triaxial testing and provides a simple means to estimate the ultimate performance limit state that corresponds to the onset of embankment slope instability. Results from a parametric study show good agreement between the numerical results and proposed analytical criterion. The proposed criterion is also compared with data from field cases reported in literature by others, and reasonably good agreement with onset of failure is obtained. Results from applying the proposed model to the case studies indicate the applicability of the proposed approach as a framework for various loading conditions, slope geometries, and material properties.}, number={4}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, publisher={American Society of Civil Engineers (ASCE)}, author={Jadid, Rowshon and Montoya, Brina M. and Gabr, Mohammed}, year={2022}, month={Apr} }
 @misc{faeli_montoya_gabr_2022, title={Reactive Transport Modeling of Microbial Induced Calcium Carbonate Precipitation Utilizing Various Configurations of Injection Wells}, url={http://dx.doi.org/10.1061/9780784484012.041}, DOI={10.1061/9780784484012.041}, abstractNote={While experimental studies on the use of microbial-induced calcium carbonate precipitation (MICP) for soil improvement have focused on assessment of cemented soil properties, there is a gap between small-scale laboratory experiments and modeling for the design of large-scale field implementation. Numerical analyses are conducted herein to explore the influence of various layouts and configurations of injection wells in delivering effective deployment of the MICP process. Metrics of evaluation include continuity and level of cementation as well as associated by-products. The bacterial transport/attachment/decay, and ureolysis rate parameters are included in the transport model. The model is calibrated using column-scale experimental data. Under the same flow rate and injected volumetric solutions, results indicated that 2-, 3-, and 4-well configurations with distance between wells equal to 1 m produce the highest average CaCO3 in the target area. Among the well configurations which induce the highest CaCO3 content, 4-well configuration with 1 m distance between wells provided more uniform distribution of CaCO3 (less standard deviation), with relatively lower by-product ammonium (NH4).}, journal={Geo-Congress 2022}, publisher={American Society of Civil Engineers}, author={Faeli, Zahra and Montoya, Brina M. and Gabr, Mohammed A.}, year={2022}, month={Mar} }
 @article{rafiei_rahman_gabr_2022, title={Response and Instability of Sloping Seabed Supporting Small Marine Structures: Wave - Structure-Soil Interaction Analysis}, volume={144}, ISSN={["1528-896X"]}, DOI={10.1115/1.4052864}, abstractNote={Abstract}, number={3}, journal={JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME}, author={Rafiei, Amin and Rahman, M. S. and Gabr, M. A.}, year={2022}, month={Jun} }
 @misc{ahmed_montoya_gabr_2022, title={Sensitivity Analyses of Hypoplastic Model Parameters to Simulate the Stress–Strain Behavior of MICP-Treated Sand}, url={http://dx.doi.org/10.1061/9780784484012.039}, DOI={10.1061/9780784484012.039}, abstractNote={Bio-mediated soil improvement has become an important research area in recent years due to the societal need for eco-friendly ground improvement solutions. This technique utilizes the hydrolyzation capacity of ureolytic bacteria to induce carbonate precipitation in order to improve the shear strength properties of sandy soil. Even though Microbial induced calcium carbonate precipitation (MICP) is now an experimentally proven technique, work remains to advance the modeling of the strain-softening pattern of bio-cemented granular soils. In general, widely used models such as conventional elasto-plastic models do not fully capture the behavior of cemented soils. Work herein explores the use of the hypoplastic constitutive model in capturing the strain-softening behavior of MICP treated soil. A sensitivity analysis is performed to investigate the influence of hypoplastic parameters needed to model the material behavior on the obtained stress–strain behavior. Hypoplastic material model parameters are calibrated and the stress–strain responses for data from drained triaxial tests have been simulated for different levels of cementation.}, journal={Geo-Congress 2022}, publisher={American Society of Civil Engineers}, author={Ahmed, Faria and Montoya, Brina M. and Gabr, Mohammed A.}, year={2022}, month={Mar} }
 @book{cui_cui_gabr_kumari_ahmed_ozcan_horri_bhattacharya_2022, title={Synergistic Hybrid Marine Renewable Energy Harvest System}, DOI={10.2139/ssrn.4415951}, abstractNote={To address the United Nations (UN) sustainable development Goal 7 and provide affordable and clean energy, economically harvesting renewable energy plays particularly important role in contributing to achieving such goal. This paper proposed a novel synergistic hybrid marine renewable energy harvesting system to improve energy production and reduce levelized costs of energy. Firstly, various marine renewable energy resources and state-of-art technologies for energy exploitation and storage were reviewed. The site selection criteria for each energy harvesting approach were identified, and a scoring matrix for site selection was proposed to screen suitable locations for the hybrid system. The Triton Knoll Wind Farm was then used as a case study to demonstrate the application of the proposed scoring matrix. The suitable energy types for this location include wind energy, wave energy, and tidal current energy, with the most suitable foundation type being monopiles. Finally, FE modeling analyses were performed to assess the effects of the additional energy harvesting structure on the structural stability and natural frequency of the main tower structure. It has been proven that the additional structures have minimum influence on the original system but increased energy yield per unit marine area.}, institution={SSRN}, author={Cui, Liang and Cui, Sadr and Gabr, Mohammed and Kumari, Wanniarachchige Gnamani Pabasara and Ahmed, Aziz and Ozcan, Hasan and Horri, Bahman Amini and Bhattacharya, Subhamoy}, year={2022}, month={Oct} }
 @article{rafiei_rahman_gabr_ghayoomi_2021, title={Analysis of wave-induced submarine landslides in nearly saturated sediments at intermediate water depths}, volume={40}, ISSN={1064-119X 1521-0618}, url={http://dx.doi.org/10.1080/1064119X.2021.2001610}, DOI={10.1080/1064119X.2021.2001610}, abstractNote={Abstract Evaluation of wave impacts on submarine landslides is an essential element in geohazard studies. The slight desaturation of sediments (due to dissociation of gas hydrates) has been found to adversely impact the slide of the sloping seabed in the Fraser River Delta in Canada. In this study, to investigate the role of wave action on the slide of partially saturated seabed slopes, an integrated FEM model is developed. Despite most earlier studies that used a simplified decoupled undrained analysis, in this article, a more realistic model for coupled flow-and-deformation processes (within the sediments) and fluid-seabed interaction is utilized. Linear wave theory and Biot’s poroelasticity for the fluid and seabed domains are considered, respectively, and continuity of flux and traction is enforced along the interface of the media. The instability of the sloping seabed is investigated using strength reduction finite element method (SRFEM) with Mohr-Coulomb failure criterion. The limitation of limit equilibrium methods in the evaluation of submarine landslides is shown through comparison with SRFEM analyses where partly-dynamic and quasi-static idealizations of seabed response are considered. Finally, the adverse impacts of slight desaturation on seabed instability are assessed, and the reduction of the stability number with seabed steepness is presented.}, number={12}, journal={Marine Georesources & Geotechnology}, publisher={Informa UK Limited}, author={Rafiei, Amin and Rahman, M. Shamimur and Gabr, Mohammed A. and Ghayoomi, Majid}, year={2021}, month={Nov}, pages={1411–1423} }
 @article{alhomair_faeli_hosseini_gabr_pour-ghaz_parker_2021, title={Assessment of Mitigation Measures against Benzene Breakthrough into Subsurface Concrete Pipe}, volume={12}, ISSN={["1949-1204"]}, DOI={10.1061/(ASCE)PS.1949-1204.0000512}, abstractNote={AbstractWork in this paper investigates the efficacy of mitigation measures to minimize the contaminant ingress into subsurface concrete pipes. The 3D study model of the concrete pipe and the soil ...}, number={1}, journal={JOURNAL OF PIPELINE SYSTEMS ENGINEERING AND PRACTICE}, author={Alhomair, Sultan and Faeli, Zahra and Hosseini, Payam and Gabr, Mohammed and Pour-Ghaz, Mohammad and Parker, Cyrus}, year={2021}, month={Feb} }
 @article{shahriar_ortiz_montoya_gabr_2021, title={Bridge Pier Scour: An overview of factors affecting the phenomenon and comparative evaluation of selected models}, volume={28}, ISSN={2214-3912}, url={http://dx.doi.org/10.1016/j.trgeo.2021.100549}, DOI={10.1016/j.trgeo.2021.100549}, abstractNote={Scour, defined by the loss of geomaterials surrounding a foundation support system, is a primary cause of bridge failure in the United States and worldwide. Work herein presents a comprehensive review of the current state of knowledge on geotechnical aspects of erodibility, factors influencing pier scour, factors complicating pier scour assessment, and databases available on erodibility and pier scour. A summary of deterministic pier scour models, developed since 1990, is presented in view of the factors affecting scour rate and equilibrium magnitude. The study discusses challenges in the predictive approaches reviewed in the paper. In addition, advancements in probabilistic pier scour models, and observation-based models are summarized. Four pier scour models, namely Wilson (1995) model, Melville (1997) model, Hydraulic Engineering Circular No. 18 (2012) model, and Briaud (2014) model are comparatively applied to data from laboratory pier scour database. Error statistics and accuracy, precision, and probabilistic distribution of predictions from these models are presented and discussed.}, journal={Transportation Geotechnics}, publisher={Elsevier BV}, author={Shahriar, Azmayeen R. and Ortiz, Alejandra C. and Montoya, Brina M. and Gabr, Mohammed A.}, year={2021}, month={May}, pages={100549} }
 @misc{rafiei_gabr_rahman_ghayoomi_2021, title={Cyclic Response and Instability Analysis of Seabed With Cohesionless Soils Due to Surging Waves}, url={http://dx.doi.org/10.1115/omae2021-62635}, DOI={10.1115/omae2021-62635}, abstractNote={Abstract}, journal={Volume 6: Ocean Engineering}, publisher={American Society of Mechanical Engineers}, author={Rafiei, Amin and Gabr, M. A. and Rahman, M. S. and Ghayoomi, Majid}, year={2021}, month={Jun} }
 @article{montoya_do_gabr_2021, title={Distribution and Properties of Microbially Induced Carbonate Precipitation in Underwater Sand Bed}, volume={147}, ISSN={["1943-5606"]}, DOI={10.1061/(ASCE)GT.1943-5606.0002607}, abstractNote={AbstractMicrobially induced carbonate precipitation (MICP) is an innovative approach to strengthening and improving loose porous media. To advance MICP implementation in various geotechnical applic...}, number={10}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, author={Montoya, Brina M. and Do, Jinung and Gabr, Mohammed A.}, year={2021}, month={Oct} }
 @article{jativa_hosseini_gabr_pour-ghaz_2021, title={Effects of MgSO4 on Calcium-Silicate-Hydrate}, volume={10}, ISSN={2379-1357}, url={http://dx.doi.org/10.1520/ACEM20210013}, DOI={10.1520/ACEM20210013}, abstractNote={Abstract}, number={1}, journal={Advances in Civil Engineering Materials}, publisher={ASTM International}, author={Jativa, Francisco W. and Hosseini, Payam and Gabr, Mohammed and Pour-Ghaz, M.}, year={2021}, month={Dec}, pages={20210013} }
 @misc{jadid_montoya_gabr_2021, title={Evaluation of Pore Water Pressure Prediction Methods under Rapid Drawdown: Case Study of the Pilarcitos Dam Failure}, url={http://dx.doi.org/10.1061/9780784483688.014}, DOI={10.1061/9780784483688.014}, abstractNote={Work in this study utilizes coupled, partially coupled, and uncoupled transient seepage analysis approaches to investigate the Pilarcitos Dam failure due to the rapid drawdown (RDD) condition. The Pilarcitos Dam is modeled using the finite-element (FE) software PLAXIS utilizing nonlinear advanced elastic–plastic constitutive relation. The modeled embankment is subjected to rapid drawdown, and the stability factor of safety (FS) is determined using the strength reduction method (SRM). The uncoupled seepage/stability approach is also applied whereas the partially coupled seepage analysis and the subsequent stability analysis are performed using FE program SEEP/W and limit equilibrium (LEM) software SLOPE/W, respectively. Results indicated that the use of coupled analyses leads to more realistic estimation of pore water pressures after RDD, as compared to the partially coupled and uncoupled analysis approaches. In this case, only the coupled analysis approach yielded representative FS and maximum depth of potential slip surface that reflect conditions observed for Pilarcitos Dam failure. In addition, the results indicated that the estimated time for complete dissipation of pore pressure after drawdown is significantly higher for uncoupled and partially coupled analyses as compared to the coupled analysis approach.}, journal={Geo-Extreme 2021}, publisher={American Society of Civil Engineers}, author={Jadid, Rowshon and Montoya, Brina M. and Gabr, Mohammed A.}, year={2021}, month={Nov} }
 @article{faeli_alhomair_hosseini_gabr_pour-ghaz_2021, title={Factors Affecting Multiphase Benzene Breakthrough into Drainage Concrete Pipe in the Unsaturated Subsurface Profile}, volume={12}, ISSN={["1949-1204"]}, DOI={10.1061/(ASCE)PS.1949-1204.0000554}, abstractNote={AbstractAnalyses presented herein explore transport aspects related to benzene breakthrough into gasketed subsurface concrete pipe embedded in an unsaturated soil profile. A series of three-dimensi...}, number={3}, journal={JOURNAL OF PIPELINE SYSTEMS ENGINEERING AND PRACTICE}, author={Faeli, Zahra and Alhomair, Sultan and Hosseini, Payam and Gabr, Mohammed and Pour-Ghaz, Mohammad}, year={2021}, month={Aug} }
 @article{shahriar_montoya_ortiz_gabr_2021, title={Quantifying probability of deceedance estimates of clear water local scour around bridge piers}, volume={597}, ISSN={0022-1694}, url={http://dx.doi.org/10.1016/j.jhydrol.2021.126177}, DOI={10.1016/j.jhydrol.2021.126177}, abstractNote={Local bridge scour, which is defined as the loss of soil particles/mass surrounding a pier foundation due to the flowing water-induced shear stresses, is a primary cause of bridge failure in the United States and worldwide. Current practice of bridge scour prediction is mostly based on the use of deterministic models. Work herein presents statistical models that extend five deterministic approaches reported in literature to predict the expected scour depth while quantifying inherent model bias and uncertainty in view of data scatter. Clear water scour database is used herein and the analyses quantify model scatter by comparatively assessing the computed scour depth versus measured data reported in the database. A relationship between probability of deceedance associated with the predicted scour depth and a modification factor (that is applied into the deterministic prediction) is devised. The modification factor allows for the use of the scour magnitude computed from the deterministic models while quantifying the probability of a computed scour depth being less than or more than a most likely value (per measurements reported in the database). The application of the proposed model is demonstrated with an example and the results are discussed.}, journal={Journal of Hydrology}, publisher={Elsevier BV}, author={Shahriar, Azmayeen R. and Montoya, Brina M. and Ortiz, Alejandra C. and Gabr, Mohammed A.}, year={2021}, month={Jun}, pages={126177} }
 @article{do_montoya_gabr_2021, title={Scour Mitigation and Erodibility Improvement Using Microbially Induced Carbonate Precipitation}, volume={44}, ISSN={["1945-7545"]}, DOI={10.1520/GTJ20190478}, abstractNote={Enhancing the scour resistance of foundation systems supporting superstructures over waterways is required for the sustainable functionality of the structure. In this article, the use of microbially induced carbonate precipitation (MICP) was investigated for the potential of its use in scour mitigation and erodibility improvement of sand. Testing was performed in a 0.91 by 1.22 by 1.22-m model box, and a double wall delivery system was developed and used to target cementation near the surface. A comparative study was performed on the scour behavior of untreated and treated samples using data from a series of flow tests. Impinging jet testing was used to evaluate the erodibility parameters of treated sand. The results from flow testing indicated that untreated and lightly cemented zones showed similar scour depth, whereas indiscernible scour was observed for the heavily cemented zone. The improvement distribution pattern throughout the media showed an ellipsoidal shape with respect to the injection source. The scour behavior and the cementation pattern indicated less cementation was achieved at the zone near the injection source because of high induced seepage velocity. Based on the impinging jet testing results, an empirical erosion model for MICP-treated sand is proposed as a function of the level of cementation.}, number={5}, journal={GEOTECHNICAL TESTING JOURNAL}, author={Do, Jinung and Montoya, Brina M. and Gabr, Mohammed A.}, year={2021}, month={Sep}, pages={1467–1483} }
 @misc{ahsanuzzaman_gabr_borden_2020, title={An Approach to Predict Unknown Diameter of Hollow-Bar Micropiles (HBMs) in Sandy Soils Considering Installation Parameters}, url={http://dx.doi.org/10.1061/9780784482780.015}, DOI={10.1061/9780784482780.015}, abstractNote={A common method for predicting ultimate shaft resistance of pile foundation in sandy soils is based on the use of effective stress and utilizing a beta-coefficient (β) that incorporates the soil-pile interface effects. The β is a function of coefficient of lateral earth pressure (defined as the ratio of the effective radial stress acting on the pile wall to the effective overburden stress, σ‘v) and the interface friction angle between pile wall and the soil. In the case of the self-drilling HBMs, the diameter of the formed pile is not known. The diameter of the HBMs varies significantly as the central hollow-bar penetrates soil at various rates and grout pump flow rates. The soil types and existing density also play an important role in forming the diameter. TITAN Injection Pile or HBM manufacturer company “Ischebeck” introduced a new term describing a widening value “a”. This value quantifies the difference between diameters of the formed HBM and the used drill-bit. The “a” value ranges from 0.8-inch (20 mm) minimum for any type of soil to 2.0 inches (50 mm) for sandy soils and 3 inches (75 mm) for gravelly soils. However, the effect of installation parameters on the formation of diameter of HBM is not addressed in previous studies. Therefore, utilizing field-measured data, work presented herein examined the effect of both the installation parameters and soil conditions on the formed HBM diameter. Multivariate regression analysis was used to develop models to predict the formed diameter of HBMs used to assess the axial pullout capacity of HBMs. Eight HBMs, four instrumented and four non-instrumented, were used in the study. The field testing program included installation of micropiles to a depth of 25 ft. (7.62 m) while varying the drill-bit insertion rate (IR) and the grout flow rate (QR). In addition, the installation methods included HBMs that were continuously drilled and grouted with neat grout water-cement ratio (w/c) of 0.4, and others that were first drilled and grouted continuously with thinner grout (w/c-0.7) and then flushed from bottom to top with thicker grout (w/c-0.4). The eight HBMs were tested for ultimate pullout capacity. Four of those instrumented HBMs were retrieved after the load testing to measure the formed diameter per foot of installation. The back-calculated diameter and pull-out test data were used multivariate regression analysis to predict the diameter of those non-instrumented and non-retrieved HBMs.}, journal={Geo-Congress 2020}, publisher={American Society of Civil Engineers}, author={Ahsanuzzaman, Mohammad and Gabr, Mohammed A. and Borden, Roy H.}, year={2020}, month={Feb} }
 @misc{faeli_alhomair_gabr_pour-ghaz_parker_2020, title={Benzene Migration in Unsaturated Profile with Subsurface Drainage Concrete Pipe}, url={http://dx.doi.org/10.1061/9780784482827.020}, DOI={10.1061/9780784482827.020}, abstractNote={The impact of benzene leakage on underlying unsaturated zone and nearby subsurface drainage concrete pipe is investigated. Work in the paper considers mass transfer into subsurface concrete pipe located in unsaturated profile. The 3D numerical simulations were implemented using the T2VOC code with the Petrasim2018 graphical user interface to analyze multiphase migration in the vadose zone and the impact on the concrete pipeline installed in a trench. The contaminant’s gas, aqueous, and free product phases are assessed based on the model physical properties of soil and concrete materials. A case study is presented with data from a site located in the coastal plain physiographic region of North Carolina (NC). The site is a gas station located near the town of Jacksonville, NC. The analyses consider the effect of depth to groundwater table and volatilization into the atmosphere. The results illustrate the transport of the three phases in unsaturated soil domain and the potential of having the gas and aqueous phases breakthrough the subsurface concrete pipe.}, journal={Geo-Congress 2020}, publisher={American Society of Civil Engineers}, author={Faeli, Z. and Alhomair, S. and Gabr, M. and Pour-Ghaz, M. and Parker, C.}, year={2020}, month={Feb} }
 @article{hosseini_alhomair_faeli_pour-ghaz_gabr_knappe_parker_2020, title={Degradation Model for the Tensile Strength of PVC and Rubber Gasket Materials Exposed to Benzene and PCE-Saturated Aqueous Solutions}, volume={2674}, ISSN={["2169-4052"]}, DOI={10.1177/0361198120906126}, abstractNote={ In this paper, a tensile strength degradation model is developed for polyvinyl chloride (PVC) pipe and three rubber gasket materials commonly used in stormwater drains and wet utilities; the degradation model considers exposure to a single contaminant at its saturation level. The contaminant considered included benzene and tetrachloroethylene (PCE) because of their prevalence. The materials considered are unplasticized Polyvinyl chloride (u-PVC) utilized as the pipe material, and three types of rubber gaskets: Polychloroprene (Neoprene-CR), Acrylonitrile (nitrile) butadiene rubber (Buna-N), and fluoroelastomer rubber (FKM—Grade A VitonTM). First, the degradation rates of these materials are experimentally quantified using accelerated testing; then using the experimental results and Williams–Landel–Ferry (WLF) method a degradation model is developed. Finally, a simplified method is introduced to relate the tensile strength degradation of PVC to the penetration rate of the contaminants. }, number={2}, journal={TRANSPORTATION RESEARCH RECORD}, author={Hosseini, Payam and Alhomair, Sultan and Faeli, Zahra and Pour-Ghaz, Mohammad and Gabr, Mohammed and Knappe, Detlef and Parker, Cyrus}, year={2020}, month={Feb}, pages={274–283} }
 @article{jadid_montoya_bennett_gabr_2020, title={Effect of repeated rise and fall of water level on seepage-induced deformation and related stability analysis of Princeville levee}, volume={266}, ISSN={["1872-6917"]}, DOI={10.1016/j.enggeo.2019.105458}, abstractNote={The Princeville levee, and flooding associated with Hurricanes Floyd and Matthew, is used as a case study in which the analyses are focused on the effect of repeated rise and fall of water levels (representing severe storm cycles) on the stability of the levee and the risk of failure. The analyses included strain-based and strength reduction approaches and are conducted using the finite element program Plaxis 2D. The limit equilibrium stability software "Slope/W" was also used for comparative study. The strain-based limit state approach considers the uncertainty of soil properties and is used to characterize the levee performance under repeated storm loading in terms of damage levels (or limit states). The strain-based analyses results show a progressive development of plastic shear strain zone within the levee as the number of storm cycles is increased. The accumulation of such shear strain leads to increasing the probability of exceeding a given performance limit state. As more flooding cycles are introduced, the shear strain values increase by a factor of 3.5 from cycle 1 to 6, and therefore reflect the increasing level of failure risk. In parallel, the deterministic stability factor of safety obtained from limit equilibrium method remains unchanged and slightly changes for strength reduction method with an increased number of rises and falls of the water level. The consideration of "rapid" drawdown conventionally used in limit equilibrium stability analyses (where no consideration for time is included), instead of more realistic rate based on drawdown hydrograph leads to conservative estimate of factor of safety. The analyses results demonstrate the increase in risk with repeated hydraulic loading.}, journal={ENGINEERING GEOLOGY}, author={Jadid, Rowshon and Montoya, Brina M. and Bennett, Victoria and Gabr, Mohammed A.}, year={2020}, month={Mar} }
 @misc{do_montoya_gabr_2020, title={Microbially Induced Carbonate Precipitation Process for Soil Improvement Adjacent to Model Pile by Innovative Delivery System}, url={http://dx.doi.org/10.1061/9780784482834.021}, DOI={10.1061/9780784482834.021}, abstractNote={Microbially induced carbonate precipitation (MICP) is an innovative approach to improve loose soil using bacteria to hydrolyze urea and facilitate the precipitation of calcium carbonate. In this paper, a proposed double wall pile delivery system is introduced to improve submerged sand adjacent to a pile foundation system using MICP. The implementation of MICP delivery system was conducted via the double wall model pile under various constant head differentials in a large-scale soil box. The level of cementation was spatially monitored during treatment using bender elements for shear wave velocity measurements. After the completion of the treatment, cone tip resistance was measured to assess the improvement with distance from the injection source. The cementation profile was also assessed by acid washing the treated sand at key locations. Stabilization results based on the use of the proposed double wall pile delivery system and associated challenges are presented and discussed.}, journal={Geo-Congress 2020}, publisher={American Society of Civil Engineers}, author={Do, Jinung and Montoya, Brina M. and Gabr, Mohammed A.}, year={2020}, month={Feb} }
 @inproceedings{alhomair_hosseini_gabr_pour-ghaz_knappe_2019, title={Breakthrough of Benzene Soluble Phase in Subsurface Domain with Concrete Utility Pipe}, ISBN={9780784482148}, number={312}, booktitle={Geo-Congress 2019: Geoenvironmental Engineering and Sustainability}, author={Alhomair, S. and Hosseini, P. and Gabr, M. and Pour-Ghaz, M. and Knappe, D.}, year={2019}, pages={115–124} }
 @misc{rafiei_rahman_gabr_2019, title={Coupled Analysis of Wave, Structure, and Sloping Seabed Interaction: Response and Instability of Seabed}, ISBN={9780784482124}, url={http://dx.doi.org/10.1061/9780784482124.019}, DOI={10.1061/9780784482124.019}, abstractNote={Instability of seabed due to wave action may cause serious damages to coastal infrastructure. The wave-induced instantaneous liquefaction near and around a structure, may impact the stability and capacity of foundation elements. The wave-seabed interaction has been mostly studied based on decoupled analysis for the flat or slightly sloping seabed (slope less than five degrees). However, some of marine structures, near shore may be built on (or anchored to) seabed with considerable slopes. In this paper, the response and instability of the sloping seabed supporting a marine structure and subjected to surface waves is evaluated. The scope included developing a numerical model using a fully coupled approach. Biot's equations of the seabed in conjunction with governing equations for other domains (structure and fluid regions) are solved simultaneously using finite element method. The instability of seabed due to wave-induced instantaneous liquefaction around the marine structure is evaluated and the effect of slope on the extent of liquefied zone is examined. The results indicated that seabed response and the extent of liquefied zone near the structure are reduced with increasing steepness of seabed. The effect of various slope steepness and soil parameters on the extent of the liquefied zone is characterized and discussed.}, journal={Geo-Congress 2019}, publisher={American Society of Civil Engineers}, author={Rafiei, Amin and Rahman, M. S. and Gabr, M. A.}, year={2019}, month={Mar} }
 @article{rafiei_rahman_gabr_2019, title={Coupled analysis for response and instability of sloping seabed under wave action}, volume={88}, url={https://doi.org/10.1016/j.apor.2019.04.017}, DOI={10.1016/j.apor.2019.04.017}, abstractNote={Wave-induced instability of seabed may cause damage to coastal and offshore structures. This issue has been investigated mostly for mildly sloping (<5°) seabed considering uncoupled or one-way coupled response of wave and seabed interaction. However, some of the marine structures are founded on seabed with steeper slopes. In this study, the wave-induced response and instability of sloping seabed are evaluated using a coupled finite element model. The interaction between fluid and porous seabed accounting for the effect of fluid motion on the seabed response, and conversely the effect of seabed response on the fluid motion (but not on the surface wave profile) is considered. The results indicate that the system response (fluid pressure, stresses, etc.) and the extent of instantaneously liquefied zone within the sloping seabed with significant steepness are lesser than those for horizontal seabed. Moreover, for typical sediment and wave characteristics, for the flat seabed, the response obtained from fully coupled analysis is not significantly different from those obtained by uncoupled analysis. For the sloping bed, such difference is slightly greater as compared to that for the flat bed.}, journal={Applied Ocean Research}, publisher={Elsevier BV}, author={Rafiei, Amin and Rahman, M.S. and Gabr, M.A.}, year={2019}, month={Jul}, pages={99–110} }
 @article{do_montoya_gabr_2019, title={Debonding of microbially induced carbonate precipitation-stabilized sand by shearing and erosion}, volume={17}, ISSN={["2005-307X"]}, DOI={10.12989/gae.2019.17.5.429}, abstractNote={Microbially induced carbonate precipitation (MICP) is an innovative soil improvement approach utilizing metabolic activity of microbes to hydrolyze urea. In this paper, the shear response and the erodibility of MICP-treated sand under axial compression and submerged impinging jet were evaluated at a low confining stress range. Loose, poorly graded silica sand was used in testing. Specimens were cemented at low confining stresses until target shear wave velocities were achieved. Results indicated that the erodibility parameters of cemented specimens showed an increase in the critical shear stress by up to three orders of magnitude, while the erodibility coefficient decreased by up to four orders of magnitude. Such a trend was observed to be dependent on the level of cementation. The treated sand showed dilative behavior while the untreated sands showed contractive behavior. The shear modulus as a function of strain level, based on monitored shear wave velocity, indicated mineral debonding may commence at 0.05% axial strain. The peak strength was enhanced in terms of emerging cohesion parameter based on utilizing the Mohr-Coulomb failure criteria.}, number={5}, journal={GEOMECHANICS AND ENGINEERING}, author={Do, Jinung and Montoya, Brina M. and Gabr, Mohammed A.}, year={2019}, month={Apr}, pages={429–438} }
 @misc{jadid_montoya_bennett_gabr_2019, title={Effects of Load History on Seepage-Induced Deformation and Associated Performance in Terms of Probability of Exceeding Limit States—Case Study of Princeville Levee}, url={http://dx.doi.org/10.1061/9780784482070.003}, DOI={10.1061/9780784482070.003}, abstractNote={This paper presents the use of strain-based analysis of Princeville levee to assess the probability of exceeding performance limit states due to the effect of repeated rise and fall of water levels, representing severe storm cycles. To this end, the Princeville levee is selected as a case study and the strain-based analyses are conducted using the finite element program Plaxis 2D. The strain-based approach considers the uncertainty of the permeability of foundation layer and treat them as random variables. Results show a progressive development of plastic shear strain within the levee as the number of storm cycles is increased. The accumulation of such shear strain leads to increasing the probability of exceeding a given performance limit state, and therefore reflect the increasing level of failure risk. In parallel, the stability factor of safety obtained from limit equilibrium approach remains unchanged while it changed slightly for strength reduction method with increased number of water level rise and fall cycles. The conventional slope stability factor of safety approaches, therefore, do not reflect the potential probability of failure sufficiently with repeated loading which negates the ability use it to perform design on the basis of meeting a risk criterion.}, journal={Geo-Congress 2019}, publisher={American Society of Civil Engineers}, author={Jadid, Rowshon and Montoya, Brina M. and Bennett, Victoria and Gabr, Mohammed}, year={2019}, month={Mar} }
 @article{montoya_safavizadeh_gabr_2019, title={Enhancement of Coal Ash Compressibility Parameters Using Microbial-Induced Carbonate Precipitation}, volume={145}, ISSN={["1943-5606"]}, DOI={10.1061/(ASCE)GT.19435606.0002036}, number={5}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, author={Montoya, Brina M. and Safavizadeh, Shahin and Gabr, Mohammed A.}, year={2019}, month={May} }
 @article{montoya_safavizadeh_gabr_2019, title={Enhancement of Coal Ash Compressibility Parameters Using Microbial-Induced Carbonate Precipitation}, volume={145}, ISSN={1090-0241 1943-5606}, url={http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0002036}, DOI={10.1061/(ASCE)GT.1943-5606.0002036}, abstractNote={AbstractMicrobial-induced calcium carbonate precipitation (MICP) was experimentally implemented on two coal ash materials (i.e., CA1 and CA3) to investigate the efficacy of the treatment on the hyd...}, number={5}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Montoya, Brina M. and Safavizadeh, Shahin and Gabr, Mohammed A.}, year={2019}, month={May}, pages={04019018} }
 @inproceedings{do_montoya_gabr_2019, title={Erosion Reduction near Spillway Foundations using Bio-Cementation}, booktitle={Proceedings from Dam Safety 2019, Association of State Dam Safety Officials (ASDSO)}, author={Do, J. and Montoya, B. and Gabr, M.}, year={2019} }
 @inproceedings{safavizadeh_montoya_gabr_knappe_2019, title={Factors Affecting the Kinetics of Urea Hydrolysis via
            <i>Sporoscarcina pasteurii}, url={http://dx.doi.org/10.1061/9780784482148.011}, DOI={10.1061/9780784482148.011}, abstractNote={Microbial induced carbonate precipitation (MICP) is a bio-mediated approach to improve engineering properties of granular materials. Cell population, substrate concentration, alkalinity, and temperature are the main factors controlling urea hydrolysis rate in the MICP process. In this study, the effects of initial substrate (urea) concentration and cell population on the rate of urea hydrolysis were evaluated using electrical conductivity as a monitoring method. For this purpose, a correlation between electrical conductivity and hydrolyzed urea concentration was derived from a batch test program. Various initial substrate concentrations and cell populations were selected in another batch test program to evaluate their contribution to the urea hydrolysis rate. Increasing both initial substrate concentration and cell population accelerated the rate as discussed in detail in this paper. Finally, a simplified column testing program was completed to demonstrate the effectiveness of electrical conductivity as a monitoring parameter during MICP treatment.}, booktitle={Geo-Congress 2019}, publisher={American Society of Civil Engineers}, author={Safavizadeh, Shahin and Montoya, Brina M. and Gabr, Mohammed A. and Knappe, Detlef R. U.}, year={2019}, month={Mar} }
 @article{gabr_2019, title={Farewell}, url={https://doi.org/10.1061/(ASCE)GT.1943-5606.0002076}, DOI={10.1061/(ASCE)GT.1943-5606.0002076}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, author={Gabr, Mohammed}, year={2019}, month={May} }
 @article{zamani_montoya_gabr_2019, title={Investigating challenges of in situ delivery of microbial-induced calcium carbonate precipitation (MICP) in fine-grain sands and silty sand}, volume={56}, ISSN={0008-3674 1208-6010}, url={http://dx.doi.org/10.1139/cgj-2018-0551}, DOI={10.1139/cgj-2018-0551}, abstractNote={ Microbial-induced calcium carbonate precipitation (MICP) is a sustainable soil improvement method with the potential for improving the engineering properties of sand and silty soils and therefore their resistance to liquefaction-inducing events. Work presented herein experimentally investigates the changes in hydraulic conductivity of fine sands and silty sands as a result of MICP treatment. In addition, numerical modeling is conducted to assess the changes in allowable injection rate and radius of influence for the delivery of the MICP process at the field scale. The hydraulic conductivity of Nevada sand and silty sand with 15% fines content decreased through MICP application with the trend of reduction being similar for both soils. Numerical modeling results show that with the progress of the MICP process, injection rates can be increased for Nevada sand, but remain unchanged for Nevada sand with 15% silt content (after MICP treatment up to a shear wave velocity about 400 m/s.) The presence of fines by itself leads to generation of higher levels of pore-water pressure during the injection process, which necessitates higher strength improvement to prevent development of excessive plastic strains. Therefore, improvement in shear strength and stiffness relative to the magnitude of the hydraulic conductivity level and its rate of change during the MICP process is a key parameter in determining the radius of treatment. }, number={12}, journal={Canadian Geotechnical Journal}, publisher={Canadian Science Publishing}, author={Zamani, Atefeh and Montoya, Brina M. and Gabr, Mohammed A.}, year={2019}, month={Dec}, pages={1889–1900} }
 @article{safavizadeh_montoya_gabr_2019, title={Microbial induced calcium carbonate precipitation in coal ash}, volume={69}, ISSN={0016-8505 1751-7656}, url={http://dx.doi.org/10.1680/jgeot.18.P.062}, DOI={10.1680/jgeot.18.P.062}, abstractNote={ The long-term storage of coal ash in impoundments can lead to concerns of structural stability as well as trace element migration to local surface water and groundwater sources. Microbial induced calcium carbonate precipitation (MICP) offers a potential approach for minimising leachability of heavy metal trace elements from coal ash by calcium carbonate cementation. In this study, a protocol for MICP treatment of coal ash has been experimentally developed. The MICP treatment is applied to three coal ashes from different power plants, and their response to the developed treatment protocol is assessed. Possible factors affecting the MICP treatment of coal ash are discussed in terms of efficacey and inhibition of the stabilisation process. For this purpose, several approaches such as shear wave velocity, electrical conductivity, pH measurement, acid washing, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were implemented. The results indicated that carbon/carbide content of the fly ash material has an important role in the efficacey of the MICP treatment process. The most likely explanation is carbon/carbide aids in the nucleation of calcium carbonate precipitation. }, number={8}, journal={Géotechnique}, publisher={Thomas Telford Ltd.}, author={Safavizadeh, Shahin and Montoya, Brina M. and Gabr, Mohammed A.}, year={2019}, month={Aug}, pages={727–740} }
 @article{tang_borden_gabr_2019, title={Model applicability for prediction of residual soil apparent cohesion}, volume={19}, ISSN={2214-3912}, url={http://dx.doi.org/10.1016/j.trgeo.2019.01.003}, DOI={10.1016/j.trgeo.2019.01.003}, abstractNote={The focus of this paper is on the measurement and prediction of unsaturated shear strength of residual soil as a function of matric suction by utilizing basic soil properties. A total of 19 unsaturated triaxial tests were performed on four groups of undisturbed residual soil specimens with different classifications and compositions. Six compacted specimens were tested and showed lower strength values than those of undisturbed specimens. The cohesion intercept due to matric suction was used to represent the strength contribution of the matric suction, thus accounting for the effect of confining pressure and effective cohesion. The feasibility of three existing models in predicting the apparent cohesion is investigated through comparing computed results to measured data from this paper and literature. A proposed regression equation, developed based on four data sets from the current research and six from the literature, shows an improved ability to predict measured apparent cohesion utilizing basic soil properties. The data set developed herein represent a significant addition to the literature on the unsaturated strength properties of natural residual soil, as sampled from the field.}, journal={Transportation Geotechnics}, publisher={Elsevier BV}, author={Tang, Chien-Ting and Borden, Roy H. and Gabr, Mohammed A.}, year={2019}, month={Jun}, pages={44–53} }
 @misc{ahsanuzzaman_smith_gabr_borden_2019, title={Quantifying the Influence of Construction Parameters on Hollow-Bar Micropiles Pullout Capacity in Sandy Soil}, url={http://dx.doi.org/10.1061/9780784482094.031}, DOI={10.1061/9780784482094.031}, abstractNote={The influences of construction parameters on the overall axial capacity of hollow-bar micropiles in sandy soils were quantified based on results from full-scale field testing. Eight micropiles were constructed at a site in the Outer Banks of North Carolina in two phases. The field testing program included installation of micropiles to a depth of 25 feet while varying the drilling or drill-bit insertion rate (IR) and the grout flow rate (QR). In addition, the installation methods included micropiles that were continuously drilled and grouted with neat grout water-cement ratio (w/c) of 0.4, and others that were first drilled and grouted continuously with thinner grout (w/c-0.7) and then flushed from bottom to top with thicker grout (w/c-0.4). Eight micropile installations were designated as Fast/Fast (w/c-0.4), Fast/Slow (w/c-0.4), Slow/Fast (w/c-0.4), Slow/Slow (w/c-0.4), Fast/Fast (w/c-0.7/0.4), Fast/Slow (w/c-0.7/0.4), Slow/Fast (w/c-0.7/0.4), and Slow/Slow (w/c-0.7/0.4). The results of pullout field load testing are presented in terms of load-displacement curves and load transfer mechanism. The load-testing results showed an appreciable high ultimate pullout capacity by using slow drilling and slow grout pumping rate (w/c-0.4) as compared to the other three approaches. The result showed that an additional 50% pullout capacity could be achieved by using Slow/Slow construction approach with w/c-0.4 grout, as compared to commonly practiced (Fast/Fast) installation approach.}, journal={Geo-Congress 2019}, publisher={American Society of Civil Engineers}, author={Ahsanuzzaman, Mohammad and Smith, W. Alex and Gabr, Mohammed A. and Borden, Roy H.}, year={2019}, month={Mar} }
 @inproceedings{jadid_montoya_gabr_2019, title={Rapid Drawdown Analysis using the Deformation-based Limit State Approach}, booktitle={Proceedings from Dam Safety 2019, Association of State Dam Safety Officials (ASDSO)}, author={Jadid, R. and Montoya, B.M. and Gabr, M.}, year={2019} }
 @article{do_montoya_gabr_2019, title={Scheme for Field Implementation of Microbially Induced Carbonate Precipitation adjacent to Pile Foundation System}, volume={309}, journal={ASCE Geotechnical Special Publication}, author={Do, J. and Montoya, B.M. and Gabr, M.A.}, year={2019}, pages={280–288} }
 @article{tang_borden_gabr_2018, title={A Simplified Direct Shear Testing Procedure to Evaluate Unsaturated Shear Strength}, volume={41}, ISSN={0149-6115}, url={http://dx.doi.org/10.1520/GTJ20150161}, DOI={10.1520/GTJ20150161}, abstractNote={The work in this paper presents a simplified and expedient procedure to evaluate unsaturated shear strength using conventional direct shear testing with tensiometer-measured suctions. Two types of residual soils are utilized in this testing program. These are classified as elastic silt (MH) and silt (ML) and were obtained from a test site in Greensboro, North Carolina. Unsaturated triaxial tests were performed to provide reference values for comparison with the measured values from the proposed direct shear testing approach. Both single stage and multistage triaxial tests were performed, and an insignificant difference in the peak stress from both approaches was found. The total cohesion intercept was used to represent the strength contribution of the matric suction in order to normalize the effect of the confining pressure. The applicability of the simplified expedient procedure in assessing shear strength of residual soils used herein was demonstrated based on the total cohesion intercepts obtained from both testing approaches. The results from the proposed approach were very similar to those obtained from the unsaturated triaxial compression tests.}, number={2}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Tang, Chien-Ting and Borden, Roy H. and Gabr, Mohammed A.}, year={2018}, month={Jan}, pages={20150161} }
 @inproceedings{gabr_kebede_kayser_dubbs_2018, title={Assessment of Scour Potential under Wave Action Using ISEEP}, ISBN={9780784481639}, url={http://dx.doi.org/10.1061/9780784481639.006}, DOI={10.1061/9780784481639.006}, abstractNote={Field testing with ISEEP was conducted at Jennette’s Pier, located in Nags Head, NC. The Pier is subjected to high energy waves on a daily basis, and one of its piles was fitted with a Nortek acoustic beams device that monitors distance from the sensor to the seabed with time. An approach is introduced for assessing the wave-induced bed shear stress and stream power as a function of the wave parameters. The data from ISEEP are used along with the estimated stream power to assess the scour rate at one of the pier’s pile. The computed results are presented for wave heights of 1–5 m and wave periods that ranged from 8 to 17 s. ISEEP data indicted two subsurface sand layers with the lower layer having smaller detachment rate coefficient. This is confirmed by the fact that the lower layer has a coarser grain size distribution with shell fragments. Using an average wave period of 17 s and an average wave height of 3.5 m, results using the ISEEP data with the proposed approach illustrated the possibility of obtaining scour levels similar in magnitude to the monitored data. A direct comparison between measured and computed results with time was however not possible since the time resolution of the collected wave parameters was too coarse, and backfilling of the scour hole with loose sand occurred with time.}, booktitle={Innovations in Geotechnical Engineering}, publisher={American Society of Civil Engineers}, author={Gabr, M. A. and Kebede, Y. A. and Kayser, M. F. and Dubbs, L. L.}, year={2018}, month={Jun} }
 @article{gabr_rasdorf_findley_butler_bert_2018, title={Closure to "Comparison of Three Retaining Wall Condition Assessment Rating Systems" by Mohammed A. Gabr, William Rasdorf, Daniel J. Findley, Cedrick J. Butler, and Steven A. Bert}, volume={24}, ISSN={["1943-555X"]}, DOI={10.1061/(ASCE)IS.1943-555X.0000447}, number={4}, journal={JOURNAL OF INFRASTRUCTURE SYSTEMS}, author={Gabr, Mohammed A. and Rasdorf, William and Findley, Daniel J. and Butler, Cedrick J. and Bert, Steven A.}, year={2018}, month={Dec} }
 @article{gabr_rasdorf_findley_butler_bert_2018, title={Comparison of Three Retaining Wall Condition Assessment Rating Systems}, volume={24}, ISSN={["1943-555X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85032731264&partnerID=MN8TOARS}, DOI={10.1061/(asce)is.1943-555x.0000403}, abstractNote={AbstractIn general, the nature of permanent earth retaining structures (ERSs) in highway engineering is well suited to the concept of asset management as a valuable tool for operational efficiency ...}, number={1}, journal={JOURNAL OF INFRASTRUCTURE SYSTEMS}, author={Gabr, Mohammed A. and Rasdorf, William and Findley, Daniel J. and Butler, Cedrick J. and Bert, Steven A.}, year={2018}, month={Mar} }
 @article{do_montoya_gabr_2018, title={Debonding of Microbially Induced Carbonate Precipitation-Stabilized Sand under Axial Compression and Impinging Jet}, journal={2018 World Congress on Advances in Civil, Environmental, and Material Research}, author={Do, J. and Montoya, B. and Gabr, M.}, year={2018} }
 @inproceedings{jadid_montoya_bennett_gabr_2018, title={Deformation-based versus Limit Equilibrium Analyses to Assess the Effect of Repeated Rise and Fall of Water Level on the Stability of Princeville Levee}, booktitle={Proceedings from Dam Safety 2018, Association of State Dam Safety Officials (ASDSO)}, author={Jadid, R. and Montoya, B.M. and Bennett, V. and Gabr, M.}, year={2018} }
 @inproceedings{safavizadeh_montoya_gabr_2018, title={Effect of Microbial Induced Calcium Carbonate Precipitation on Compressibility and Hydraulic Conductivity of Fly Ash}, url={http://dx.doi.org/10.1061/9780784481592.008}, DOI={10.1061/9780784481592.008}, abstractNote={The morphology and chemical composition of fly ash render the material unique in comparison to natural sediments. Fly ash deposited in ash ponds can possess a loose, saturated, and contractive structure with a tendency to collapse under induced shear stresses. Compressibility and hydraulic conductivity are the two main parameters affecting the stability of this material in ash ponds. Microbial induced calcium carbonate precipitation (MICP) is a novel approach, which has been widely studied to improve engineering properties of soils. In this study, the MICP treatment process is applied to a Class-F fly ash material to assess its effect on the two mentioned parameters. Modified odometer testing was developed with the ability to inject the treatment solution, measure the induced pressure during injection, and monitor the shear wave velocity of the test specimens. The specimens were successfully treated using MICP, reaching predetermined target shear wave velocities. The results of compressibility on treated and untreated specimens indicate that MICP decreases the compressibility of the studied material while the hydraulic conductivity decreased by only one order of magnitude or less. The shear wave velocity of the treated and untreated specimens converged to the same value while the vertical applied stress increased, indicating the calcium carbonate bond breakage between particles.}, number={296}, booktitle={IFCEE 2018}, publisher={American Society of Civil Engineers}, author={Safavizadeh, Shahin and Montoya, Brina M. and Gabr, Mohammed A.}, year={2018}, month={Jun}, pages={69–79} }
 @inproceedings{ahsanuzzaman_gabr_borden_2018, title={Effect of seawater on the mechanical properties of cement grout used for formation of micropiles in marine applications}, DOI={10.1061/9780784481592.039}, abstractNote={The deployment of ocean-based renewable energy generation devices, including those utilizing wind, waves, and tidal and ocean currents, requires the installation of cost-effective anchoring foundations. Micropiles provide a viable option for cost-effective subsea anchoring foundations. However, due to the lack of an acceptable approach for the subsea formation of micropiles in sandy soils, no cases that we are aware of have been presented in the literature. The research work reported in this article seeks to investigate the effect of seawater during mixing and curing on compressive strength (fc′) of cement grout for marine micropile anchor systems. Grout mixes are tested at three water-cement ratios (w/c) and in two different curing liquids. Specimens mixed with and cured in fresh water are designated by (ff), those mixed with and cured in seawater as (ss) and those mixed with fresh water and cured in seawater as (fs). A total of 162 cubes and 162 cylinders were cast and exposed to curing liquids for 7, 14, 28, and 90 days. The results showed an appreciable high and early fc′ gain of ss specimens compared to the baseline ff specimens. The rate of fc′ gain of ss specimens reduced slightly at low w/c ratio, but increased at higher w/c ratios (0.5 and 0.6). The reasons for such behavior are related to the accelerated rate of hydration of alite and belite due to the presence of chloride ions (Cl−) in seawater, and the transformation of ettringite (AFt) to monosulfate (AFm) or monochloroaluminate. Scanning electron microscopy (SEM) showed the formation of those crystals at discrete Cl− locations. The ff and fs specimens showed similar rate of fc′ gain (that was not affected by curing in seawater) due to the formation of impermeable layers of brucite [Mg (OH)2] and aragonite (CaCO3) beneath the surface of the fs specimens.}, number={296}, booktitle={Ifcee 2018: innovations in ground improvement for soils, pavements, and subgrades}, author={Ahsanuzzaman, M. and Gabr, Mohammed and Borden, R. H.}, year={2018}, pages={394–403} }
 @misc{montoya_do_gabr_2018, title={Erodibility of Microbial Induced Carbonate Precipitation-Stabilized Sand under Submerged Impinging Jet}, url={http://dx.doi.org/10.1061/9780784481592.003}, DOI={10.1061/9780784481592.003}, abstractNote={Scour adjacent to foundation systems is a contributing factor to significant structural damage. Microbial induced carbonate precipitation (MICP) is investigated as an approach to improve the soil's shear strength and stiffness and reduce the potential to scour. In this study, a submerged impinging jet system (mini JET apparatus) is used to assess the erodibility of MICP-treated sand with results presented in the context of data in literature. The results indicated that the critical shear stresses of the MICP-treated specimens increased one to three orders of magnitude, while the erodibility coefficients decreased by up to four orders of magnitude as the cementation level increases. The micro image analysis confirmed that cementation is achieved via precipitated calcium carbonate at the particle contacts. These results suggest that moderate to high levels of cementation using the MICP process is potentially an effective approach to reduce the sand's erodibility.}, number={296}, journal={IFCEE 2018}, publisher={American Society of Civil Engineers}, author={Montoya, Brina M. and Do, Jinung and Gabr, Mohammed M.}, year={2018}, month={Jun}, pages={19–28} }
 @inproceedings{aguirre-realpe_kowalsky_nau_gabr_2018, title={Performance Limit States of Reinforced Concrete-Filled Steel Tube Drilled Shafts}, booktitle={Eleventh U.S. National Conference on Earthquake Engineering Integrating Science, Engineering & Policy}, author={Aguirre-Realpe, Diego A. and Kowalsky, M.J. and Nau, J.M. and Gabr, M.A.}, year={2018} }
 @article{hamed mousavi_gabr_borden_2018, title={Resilient modulus prediction of soft low-plasticity Piedmont residual soil using dynamic cone penetrometer}, volume={10}, ISSN={1674-7755}, url={http://dx.doi.org/10.1016/j.jrmge.2017.10.007}, DOI={10.1016/j.jrmge.2017.10.007}, abstractNote={Dynamic cone penetrometer (DCP) has been used for decades to estimate the shear strength and stiffness properties of the subgrade soils. There are several empirical correlations in the literature to predict the resilient modulus values at only a specific stress state from DCP data, corresponding to the predefined thicknesses of pavement layers (a 50 mm asphalt wearing course, a 100 mm asphalt binder course and a 200 mm aggregate base course). In this study, field-measured DCP data were utilized to estimate the resilient modulus of low-plasticity subgrade Piedmont residual soil. Piedmont residual soils are in-place weathered soils from igneous and metamorphic rocks, as opposed to transported or compacted soils. Hence the existing empirical correlations might not be applicable for these soils. An experimental program was conducted incorporating field DCP and laboratory resilient modulus tests on "undisturbed" soil specimens. The DCP tests were carried out at various locations in four test sections to evaluate subgrade stiffness variation laterally and with depth. Laboratory resilient modulus test results were analyzed in the context of the mechanistic-empirical pavement design guide (MEPDG) recommended universal constitutive model. A new approach for predicting the resilient modulus from DCP by estimating MEPDG constitutive model coefficients (k1, k2 and k3) was developed through statistical analyses. The new model is capable of not only taking into account the in situ soil condition on the basis of field measurements, but also representing the resilient modulus at any stress state which addresses a limitation with existing empirical DCP models and its applicability for a specific case. Validation of the model is demonstrated by using data that were not used for model development, as well as data reported in the literature.}, number={2}, journal={Journal of Rock Mechanics and Geotechnical Engineering}, publisher={Elsevier BV}, author={Hamed Mousavi, S. and Gabr, Mohammed A. and Borden, Roy H.}, year={2018}, month={Apr}, pages={323–332} }
 @article{aguirre_kowalsky_nau_gabr_lucier_2018, title={Seismic performance of reinforced concrete filled steel tube drilled shafts with inground plastic hinges}, volume={165}, ISSN={0141-0296}, url={http://dx.doi.org/10.1016/j.engstruct.2018.03.034}, DOI={10.1016/j.engstruct.2018.03.034}, abstractNote={The seismic performance of reinforced concrete-filled steel tube (RCFST) drilled shafts, also known as RCFST pile-columns, was examined based on experimental tests conducted on twelve half-scale RCFST specimens at the soil-structure interaction facility at the North Carolina State University, Constructed Facilities Laboratory (NCSU-CFL). The specimens consisted of steel tubes with diameter-to-thickness (D/t) ratios ranging from 48 to 95 that were filled with reinforced concrete. Spirally welded steel tubes with outer diameters (D) of 12″ (305 mm) and 12–3/4″ (324 mm) were utilized. The specimens were tested with aboveground-to-diameter (La/D) ratios of 5.5 and 7.5, and they were embedded 14′ (4270 mm) into poorly graded sand (SP). Different levels of soil stiffness were induced in the sand by using a soil-sandwich approach, which allowed for modifying the soil stiffness profile by means of applying a surcharge on the soil surface. Cyclic lateral load was applied by a 100-kip (445 kN), 70-in. (1780 mm) stroke hydraulic actuator, supported on a braced steel frame, and pin-connected to the pile-column head ensuring that the plastic hinge developed below ground. The failure mechanism was controlled by the tensile strain in the steel tube and it was caused by a combination of tube local buckling and tube fracture. First, tube local buckling developed outward at the extreme compression fiber of the section. Tube fracture then occurred in the section with the largest buckle and it extended around about half of the section perimeter. The plastic hinge developed at depths of 2D to 4D. Onset of tube local buckling was observed at higher displacement ductility levels (µ = 3) for specimens using thicker tubes (D/t = 48) than for those using thinner tubes (D/t = 95). The force-displacement response, tensile strain distribution, and hysteretic equivalent viscous damping are discussed in this paper.}, journal={Engineering Structures}, publisher={Elsevier BV}, author={Aguirre, D.A. and Kowalsky, M.J. and Nau, J.M. and Gabr, M. and Lucier, G.}, year={2018}, month={Jun}, pages={106–119} }
 @inproceedings{montoya_safavizadeh_gabr_2018, title={Soil behavior and mineral composition of bio-cemented sands in the presence of calcium and magnesium ions}, booktitle={Proceedings: B2G}, author={Montoya, B.M. and Safavizadeh, S.S. and Gabr, M.A.}, year={2018} }
 @article{safavizadeh_montoya_gabr_2018, title={Treating Coal Ash with Microbial-Induced Calcium Carbonate Precipitation}, volume={144}, ISSN={1090-0241 1943-5606}, url={http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001956}, DOI={10.1061/(ASCE)GT.1943-5606.0001956}, number={11}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Safavizadeh, S. and Montoya, B. M. and Gabr, M. A.}, year={2018}, month={Nov}, pages={02818003} }
 @article{gabr_2017, title={2016: A Year in Review}, volume={143}, ISSN={["1943-5606"]}, url={https://doi.org/10.1061/(ASCE)GT.1943-5606.0001730}, DOI={10.1061/(asce)gt.1943-5606.0001730}, number={5}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed}, year={2017}, month={May} }
 @article{tang_borden_gabr_2017, title={Approach for Estimating Effective Friction Angle from Cone Penetration Test in Unsaturated Residual Soils}, volume={143}, ISSN={1090-0241 1943-5606}, url={http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0001799}, DOI={10.1061/(ASCE)GT.1943-5606.0001799}, abstractNote={AbstractThis paper proposes approaches to estimate effective friction angle from cone tip resistance with incorporation of matric suction. Cone penetration tests (CPTs) are performed in unsaturated...}, number={11}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Tang, Chien-Ting and Borden, Roy H. and Gabr, Mohammed A.}, year={2017}, month={Nov}, pages={04017087} }
 @inproceedings{mousavi_gabr_borden_2017, title={Assessment of Subgrade Soils Stabilization Criteria}, booktitle={International Conference on Highway Pavements & Airfield Technology}, author={Mousavi, H. and Gabr, M.A. and Borden, R.H.}, year={2017} }
 @inproceedings{bennett_jones_bekaert_bond_helal_dudas_gabr_abdoun_2017, title={Deformation Monitoring for the Assessment of Sacramento Delta Levee Performance}, ISBN={9780784480717}, url={http://dx.doi.org/10.1061/9780784480717.003}, DOI={10.1061/9780784480717.003}, abstractNote={The Sacramento Delta levee network plays a vital role in supporting the United States’ largest agricultural production and the municipal water supply for millions of people. Beyond the potential for earthquake-induced failure, performance monitoring of the levee system on the network level and the assessment of potential distress levels are needed for the maintenance and rehabilitation of this system. In this case, critical deformation needs to be assessed especially in view of the levees age, sea level rise, and ongoing subsidence due to the decomposition of the peat foundation layer. The work presented herein describes the remote sensing of a levee section deformation with time. The levee section is located on Sherman Island, CA, and monitoring was conducted in situ by GPS, in addition to remote sensing by airborne synthetic aperture radar and satellite systems. Coupled deformation/seepage numerical analysis of the levee section is performed using PLAXIS. The numerical model included characterization of the unsaturated-saturated zones and the peat foundation layer. Key parameters of the peat layer were synthesized from published data to provide baseline assessment for the current condition of the levee system in view of the measured rate of deformation.}, booktitle={Geo-Risk 2017}, publisher={American Society of Civil Engineers}, author={Bennett, Victoria and Jones, Cathleen and Bekaert, David and Bond, Jason and Helal, Amr and Dudas, Joel and Gabr, Mohammed and Abdoun, Tarek}, year={2017}, month={Jun} }
 @inproceedings{safavizadeh_montoya_gabr_2017, title={Effect of Bio-Cementation on Performance of Coal Ash Ponds}, booktitle={Proceedings from Dam Safety 2017, Association of State Dam Safety Officials (ASDSO)}, author={Safavizadeh, S.S. and Montoya, B.M. and Gabr, M.}, year={2017} }
 @inproceedings{safavizadeh_montoya_gabr_2017, title={Effect of Microbial Induced Calcite Precipitation on Compressibility and Hydraulic Conductivity of Coal Fly Ash}, booktitle={Dam Safety 2017}, author={Safavizadeh, Shahin and Montoya, Brina M. and Gabr, Mohammed A.}, year={2017} }
 @inproceedings{ardebili_gabr_rahman_2017, title={Effect of the Keying Angle on the Pullout Capacity of Suction Embedded Plate Anchor (SEPLA) in Clay}, booktitle={ISOPE-I-17-089, The International Society of Offshore and Polar Engineers}, author={Ardebili, Zahra Aghazadeh and Gabr, M.A. and Rahman, M.S.}, year={2017}, month={Jun} }
 @inproceedings{do_montoya_gabr_2017, title={Mechanical Behavior of Sands Treated by Microbially Induced Calcite Precipitation at Low Confining Stress}, booktitle={19th International Conference on Soil Mechanics and Geotechnical Engineering}, author={Do, Jinung and Montoya, Brina M. and Gabr, M.A,}, year={2017}, month={Sep} }
 @misc{helal_bennett_gabr_borden_abdoun_2017, title={Monitoring and Modeling of Peat Decomposition in Sacramento Delta Levees}, url={http://dx.doi.org/10.1061/9780784480458.054}, DOI={10.1061/9780784480458.054}, abstractNote={The integrity and reliability of levees are essential components of homeland safety. The failure of such systems due to a natural or manmade hazard can have monumental repercussions, sometimes with dramatic consequences on human life, property and the country’s economy. This paper presents some results of integrated monitoring and modeling to assess the performance-based response of a levee section. The modeled levee is part of the Whale’s Mouth section on Sherman Island where satellite images and in-ground GPS sensors are used for displacement measurements. The Whale’s Mouth levee is modeled using the large deformation option of the finite element program PLAXIS 2D. The model is used to establish a deterministic performance response under maximum water level loading and to investigate the effect of peat decomposition on the deformation response of the levee section. The remote sensing and in situ data are used to calibrate the numerical model. The results are compared to the pre-defined limit state and illustrate how the peat layer decomposition affects the modeled levee section performance. The concept of performance limit states of these critical structures provides a means to quantitatively assess the functionality of an earth structure under severe storm loading events. The probability of exceeding a prescribed limit state is defined based on the strain or gradient levels in potential emerging failure zones. The variation in strength properties and hydraulic conductivity of the levee embankment, as well as the rate of rising water level and duration of flooding, may lead to the progression of the structure state from a low probability of exceeding adequate functionality to the probability of exceeding a high limit state, i.e., imminent failure. The displacement data collected during these loading and unloading events is used to establish the levee condition assessment on the basis of the performance limit states.}, journal={Geotechnical Frontiers 2017}, publisher={American Society of Civil Engineers}, author={Helal, Amr and Bennett, Victoria and Gabr, Mo and Borden, Roy H. and Abdoun, Tarek}, year={2017}, month={Mar} }
 @article{mousavi_gabr_borden_2017, title={Optimum location of geogrid reinforcement in unpaved road}, volume={54}, ISSN={0008-3674 1208-6010}, url={http://dx.doi.org/10.1139/cgj-2016-0562}, DOI={10.1139/cgj-2016-0562}, abstractNote={This study evaluated the optimum location of a reinforcement layer to maximize the efficiency of the reinforcement inclusion in an unpaved road section. The analyses are used to investigate the optimum location of the reinforcement layer within the aggregate base course (ABC) layer, and provide a possible reason for the improvement in performance. A series of three-dimensional finite element method analyses was performed, and the strain and stress response of a reinforced unpaved road section with two different ABC thicknesses was evaluated. The analyses were conducted under cyclic loading with three different radii of the circular loaded area. The embedded depth of reinforcement was varied within the ABC layer. Results indicate that regardless of ABC layer thickness, the surface deformation is minimized when the reinforcement is embedded at a depth equal to half of the radius of the loaded area (D = 0.5r). A higher tension force is mobilized in the reinforcement element when it is placed at D = 0.5r. It is also shown that the required thickness of ABC is reduced when the reinforcement layer is implemented at the depth at which the maximum vertical strain occurs. Depending on the thickness of the ABC layer, the finite element analysis results indicate that the reinforcement layer could be ineffectual if it is placed at the interface between the ABC and the subgrade layer as is traditionally the case.}, number={7}, journal={Canadian Geotechnical Journal}, publisher={Canadian Science Publishing}, author={Mousavi, S. Hamed and Gabr, Mohammed A. and Borden, Roy H.}, year={2017}, month={Jul}, pages={1047–1054} }
 @article{mousavi_gabr_borden_2017, title={Subgrade resilient modulus prediction using light-weight deflectometer data}, volume={54}, ISSN={0008-3674 1208-6010}, url={http://dx.doi.org/10.1139/cgj-2016-0062}, DOI={10.1139/cgj-2016-0062}, abstractNote={ Resilient modulus has been used for decades as an important parameter in pavement structure design. Resilient modulus, like other elasticity moduli, increases with increasing confining stress and decreases with increasing deviatoric stress. Several constitutive models have been proposed in the literature to calculate resilient modulus as a function of stress state. The most recent model, recommended by the Mechanistic–empirical pavement design guide (MEPDG) and used in this paper, calculates resilient modulus as a function of bulk stress, octahedral shear stress, and three fitting coefficients: k1, k2, and k3. Work in this paper presents a novel approach for predicting resilient modulus of subgrade soils at various stress levels based on light-weight deflectometer (LWD) data. The proposed model predicts the MEPDG resilient modulus model coefficients (k1, k2, and k3) directly from the ratio of applied stress to surface deflection measured during LWD testing. The proposed model eliminates uncertainties associated with needed input parameters for surface modulus (ELWD) calculation, such as the selection of an appropriate value of Poisson’s ratio for the soil layer and shape factor. The proposed model was validated with independent data from other studies reported in the literature. }, number={3}, journal={Canadian Geotechnical Journal}, publisher={Canadian Science Publishing}, author={Mousavi, S. Hamed and Gabr, Mohammed A. and Borden, Roy H.}, year={2017}, month={Mar}, pages={304–312} }
 @inproceedings{bennett_nguyen_abdoun_helal_gabr_jones_bekaert_dudas_2017, title={Use of remote-sensing deformation monitoring for the assessment of levee section performance limit state}, booktitle={Proceeding of the 19th International conference on soil mechanics and geotechnical engineering}, author={Bennett, V. and Nguyen, C. and Abdoun, T. and Helal, A. and Gabr, M. and Jones, C. and Bekaert, D. and Dudas, J.}, year={2017} }
 @article{mousavi_gabr_borden_2016, title={Correlation of dynamic cone penetrometer index to proof roller test to assess subgrade soils stabilization criterion}, volume={12}, ISSN={1938-6362 1939-7879}, url={http://dx.doi.org/10.1080/19386362.2016.1272751}, DOI={10.1080/19386362.2016.1272751}, abstractNote={The proof roller test has been traditionally carried out as a technique for subgrade quality assessment in road construction and the induced pumping and permanent deformation are used as the basis for subgrade’s pass/fail criteria. The objective of the study presented herein is to assess the feasibility of using the dynamic cone penetrometer index, DCPI, to discern the need for undercut and the quality of subgrade. A series of 3D FEM analysis was performed to develop a subgrade stabilization recommendation chart, based on the predicted properties from DCPI and deformation response under cyclic proof roll loading. The ‘not passing’ criterion (will be referred to herein as ‘failure’ criterion) was determined as a 25 mm permanent deformation under proof roll test. It was determined that the failure deformation occurs at DCPI value of 38 mm/blow for single layer subgrade soil with the Mr/E50 of 6, ratio of resilient modulus to the secant modulus at 50% shear failure. These results are consistent with NCDOT 38 mm/blow undercut criteria. The numerical results indicated that the subgrade with 300 mm stiff layer (DCPI < 20 mm/blow) on top does not require any subgrade soil stabilization given the assumed properties of the underlying layers. On the other hand, the results indicated that subgrade stabilization is required where top 300 mm of the subgrade is a very soft soil layer (DCPI > 60 mm/blow), unless the sublayers underneath are composed of stiff soil (DCPI < 20 mm/blow).}, number={3}, journal={International Journal of Geotechnical Engineering}, publisher={Informa UK Limited}, author={Mousavi, S. Hamed and Gabr, Mohammed A. and Borden, Roy H.}, year={2016}, month={Dec}, pages={284–292} }
 @article{rasdorf_butler_findley_gabr_bert_2016, title={Framework for Defining Asset Features to Monitor and Assess Earth-Retaining Structures}, volume={2579}, ISSN={["2169-4052"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85014465205&partnerID=MN8TOARS}, DOI={10.3141/2579-02}, abstractNote={ Permanent earth-retaining structures (ERSs), including retaining walls, have been systematically managed, inventoried, and assessed by several government organizations, including the City of Cincinnati, Ohio; the Oregon and Pennsylvania Departments of Transportation; and the Central Federal Lands Highway Division of FHWA (for the National Park Service). For a comprehensive ERS asset management program, a careful evaluation of the structural health, criticality, and risk of ERSs is essential for proper management (preservation, rehabilitation, or replacement) of these aging assets. However, many transportation agencies struggle with the evaluation and incorporation of risk in their ERS management programs. This study addressed the development of a framework that would evaluate risk and would define its relationship to ERS condition (likelihood of failure) and ERS criticality (consequence of failure). A methodology for relating risk to routine inspection cycles for ERSs and remedial actions for those in distress is proposed. }, number={2579}, journal={TRANSPORTATION RESEARCH RECORD}, publisher={Transportation Research Board}, author={Rasdorf, William and Butler, Cedrick J. and Findley, Daniel J. and Gabr, Mohammed A. and Bert, Steven A.}, year={2016}, pages={8–16} }
 @article{gabr_butler_rasdorf_findley_bert_2016, title={Highway Retaining Walls are Assets: A Risk-Based Approach for Managing Them}, volume={20}, ISSN={1529-2975 2766-9122}, url={http://dx.doi.org/10.1061/geosek.0000320}, DOI={10.1061/geosek.0000320}, abstractNote={Throughout history, retaining walls (RWs) have served a vital role in supporting civil infrastructure. The ruins of dry stone walls that purportedly supported the hills and slopes of ancient Rome can be seen today in the underground corridors of the Colosseum, and within the ruins of the Forum and Circus Maximus. Within our National Highway System, retaining walls are an integral part of bridge abutments, grade separations, and highway embankments, and in many situations are used to support and protect transportation assets such as roads, rivers, and railways. Compared to pavements and bridges, retaining walls require less maintenance. However, and perhaps due to such success, records of wall construction, design, and performance are minimal.}, number={2}, journal={GEOSTRATA Magazine}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mo and Butler, Cedrick and Rasdorf, William and Findley, Daniel J. and Bert, Steven A.}, year={2016}, month={Mar}, pages={66–72} }
 @inproceedings{ahsanuzzaman_gabr_2016, title={Proposed Anchoring Systems for Gulf Stream (Gs) Renewable Energy Devices Accounting for Potential of GS Meandering}, booktitle={3rd Marine Energy Technical Symposium, National Hydropower Association}, author={Ahsanuzzaman, Md and Gabr, M.A.}, year={2016}, month={Apr} }
 @article{butler_gabr_rasdorf_findley_chang_hammit_2016, title={Retaining Wall Field Condition Inspection, Rating Analysis, and Condition Assessment}, volume={30}, ISSN={0887-3828 1943-5509}, url={http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000785}, DOI={10.1061/(asce)cf.1943-5509.0000785}, abstractNote={In the past, highway retaining walls were assets that were often excluded from inventory programs and were regarded as noncritical or lost assets. With the recognition that wall failures may be detrimental to the roadway and the surroundings and may pose potential hazards to the safety of the public, several highway agencies have begun to incorporate retaining walls into their inventory and inspection programs. Work in this paper addresses the development of a system for the inventory and condition assessment of retaining walls serving various functions within the highway infrastructure. Critical elements of data collection are identified and a retaining wall information collection and assessment system (WICAS) is proposed. WICAS is designed such that data can be readily collected in the field. A condition assessment model is also proposed and is used to define a retaining wall rating metric. The rating system is designed so that those elements of a wall that are deemed to be in critical distress conditions are readily identified and not overlooked through the presentation of an overall average rating for the entire wall.}, number={3}, journal={Journal of Performance of Constructed Facilities}, publisher={American Society of Civil Engineers (ASCE)}, author={Butler, Cedrick J. and Gabr, Mohammed A. and Rasdorf, William and Findley, Daniel J. and Chang, Jeffrey C. and Hammit, Britton E.}, year={2016}, month={Jun} }
 @article{aghazadeh ardebili_gabr_rahman_2016, title={Uplift Capacity of Plate Anchors in Saturated Clays: Analyses with Different Constitutive Models}, volume={16}, ISSN={1532-3641 1943-5622}, url={http://dx.doi.org/10.1061/(ASCE)GM.1943-5622.0000518}, DOI={10.1061/(asce)gm.1943-5622.0000518}, abstractNote={AbstractEvaluation of the uplift capacity of plate anchors in saturated clay is an important aspect in the design of offshore foundation systems of various structures. In most of the literature reviewed, simple constitutive models such as Tresca or Mohr–Coulomb (MC) have been used in evaluating the plates’ pullout capacity. There exists a need to study the pullout capacity of anchors using other advanced soil models and explore differences in computed behavior. In addition to the MC model, two other constitutive models are used herein to represent the soil behavior. These are Modified Cam-Clay and Soft Soil models. A series of finite-element analyses are performed using the three constitutive models. Undrained effective stress analyses are conducted to study the response of both strip and circular plate anchors in saturated soils. The capacities of plate anchors are assessed through the application of the displacement control approach. The effective stress parameters are correlated with the undrained shea...}, number={2}, journal={International Journal of Geomechanics}, publisher={American Society of Civil Engineers (ASCE)}, author={Aghazadeh Ardebili, Zahra and Gabr, M. A. and Rahman, M. S.}, year={2016}, month={Apr} }
 @article{gabr_2016, title={Year in Review}, volume={142}, DOI={10.1061/(asce)gt.1943-5606.0001510}, number={5}, journal={J. Geotech. Geoenviron. Eng.}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed}, year={2016}, month={May}, pages={01616001} }
 @article{khalilzad_gabr_hynes_2015, title={Assessment of remedial measures to reduce exceedance probability of performance limit states in embankment dams}, volume={67}, DOI={10.1016/j.compgeo.2015.02.010}, abstractNote={Results of a series of numerical analyses, simulating three remedial measures applied to an embankment dam, are used to investigate the extent of lessening the severity of the distress level under flood loading. Conceptually, the three remedial measures are increasing the mean effective stress, adding a low permeability curtain to limit seepage, and improving drainage to lower pore water pressure magnitudes at key locations. The results are presented in the context of exceeding predefined limit states in terms of toe deformation and hydraulic gradient. Constructing a downstream berm has a significant impact on the exceedance probabilities of the deformation limit states at the toe, but a small impact on the toe gradient values. Adding a low permeability curtain below the dam crest considerably reduces both deformation and gradient magnitudes in relation to the predefined limit states. This occurs due to an increased seepage path leading to a higher drop of pressure head and lower phreatic surface level; these two effects result in lower shear strains and less deformations at the toe. Improvement was observed by adding the toe drainage system with a hydraulic conductivity that is 4–20 times higher than the hydraulic conductivity of the embankment material. In this case, the exceedance probabilities of deformation limit states decrease and the impact is higher for a higher hydraulic conductivity of the drainage system compared to the embankment soil. Given the analyses configurations and parameters, constructing a berm at the toe leads to the lowest exceedance probabilities, in terms of deformation limit state, and thus seems to be the most effective approach among the three analyzed remedial measures.}, journal={Computers and Geotechnics}, publisher={Elsevier BV}, author={Khalilzad, Mahdi and Gabr, Mohammed A. and Hynes, Mary Ellen}, year={2015}, month={Jun}, pages={213–222} }
 @inproceedings{gabr_xiao_2015, title={Configuration and Anchoring of Offshore Compressed Air Energy Storage (OCAES) System}, booktitle={14th International Conference on Structural & Geotechnical Engineering (ICSGE14)}, author={Gabr, M.A. and Xiao, J.}, year={2015}, month={Dec} }
 @article{khalilzad_gabr_hynes_2015, title={Deformation-Based Limit State Analysis of Embankment Dams Including Geometry and Water Level Effects}, volume={15}, ISSN={1532-3641 1943-5622}, url={http://dx.doi.org/10.1061/(ASCE)GM.1943-5622.0000435}, DOI={10.1061/(asce)gm.1943-5622.0000435}, abstractNote={AbstractThe research presented in this paper is focused on the effect of various parameters on the deformation response of embankment dams and the corresponding performance limit states. The parameters considered include the geometry of the embankment and hydraulic loading in terms of intensity, duration, and cycles of loading and unloading as a result of the rise and fall of the water level in the reservoir. The analysis of a model embankment dam is conducted using the finite-element approach and the results are incorporated into simplified deformation-based probabilistic analyses. The effect of the change in geometry on shear strains and horizontal deformations and the corresponding probabilities of exceeding three predefined limit states are presented. The analyses are also used to demonstrate the importance of taking into account the storm loading history when assessing the stability of the flood protection earth structures under future flood events. In a larger embankment model, the shear zone propag...}, number={5}, journal={International Journal of Geomechanics}, publisher={American Society of Civil Engineers (ASCE)}, author={Khalilzad, Mahdi and Gabr, M. A. and Hynes, Mary Ellen}, year={2015}, month={Oct} }
 @article{you_lee_gabr_2015, title={Experimental Evaluation of Recycled Aggregate Porous Concrete Piles for Soft Ground Improvement}, volume={34}, ISSN={1064-119X 1521-0618}, url={http://dx.doi.org/10.1080/1064119X.2015.1076913}, DOI={10.1080/1064119x.2015.1076913}, abstractNote={The use of sand compaction pile or gravel compaction pile is nowadays a common approach for soft ground improvement. In this article, a recycled aggregate porous concrete pile has been developed by replacing natural aggregates with recycled aggregates to overcome issues related to bulging failure or reduced section geometries. Such issues may arise during installation and during the early stages of operation. In addition, the proposed approach utilizes recycled aggregates instead of natural materials. To investigate the applicability of the recycled aggregate porous concrete pile method as a ground improvement technique, a series of laboratory model consolidation tests was performed on soft clay soil reinforced with sand compaction pile, gravel compaction pile, and recycled aggregate porous concrete pile, respectively. The results indicated that the settlement reduction effect of recycled aggregate porous concrete pile was significantly higher than the sand compaction pile and gravel compaction pile methods. The stress sharing ratio from the experimental program showed good agreement with those calculated by elasticity theory. Comparative analyses of the recycled aggregate porous concrete pile versus sand compaction pile and gravel compaction pile approaches, under the same replacement area ratio and surcharge pressure, showed significantly improved consolidation time, settlement reduction, and stress sharing effect.}, number={8}, journal={Marine Georesources & Geotechnology}, publisher={Informa UK Limited}, author={You, Seung-Kyong and Lee, Jintae and Gabr, Mohammed A.}, year={2015}, month={Aug}, pages={712–720} }
 @article{gabr_xiao_rahman_2015, title={Plastic Flow of Sand and Pullout Capacity of Suction Caissons}, volume={141}, ISSN={1090-0241 1943-5606}, url={http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0001331}, DOI={10.1061/(asce)gt.1943-5606.0001331}, abstractNote={A suction caisson has a relatively small length-to-diameter ratio, and the suction-induced seepage forces can liquefy the sand surrounding the caisson, depending on the pullout rate. Houlsby et al. (2005) modeled the seepage forces effect, and its related impact on the effective stresses and the corresponding pullout capacity. However, ignoring potential liquefaction and sand flow that may occur due to the seepage-induced forces can yield an overestimate of pullout capacity as a function of the induced deformation. A Bingham plastic flow model is used to describe the shear stresses as a function of shear strain rate. The general rheological behavior is expressed as when sand flow occurs}, number={8}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Xiao, J. and Rahman, M. S.}, year={2015}, month={Aug}, pages={02815002} }
 @inproceedings{vanzwieten_baxley_alsenas_meyer_muglia_lowcher_bane_gabr_he_hudon_et al._2015, title={SS Marine Renewable Energy – Ocean Current Turbine Mooring Considerations}, DOI={10.4043/25965-ms}, abstractNote={Abstract}, booktitle={Offshore Technology Conference}, publisher={Society of Petroleum Engineers (SPE)}, author={VanZwieten, J.H. and Baxley, W.E. and Alsenas, G.M. and Meyer, I. and Muglia, M. and Lowcher, C. and Bane, J. and Gabr, M. and He, R. and Hudon, T. and et al.}, year={2015} }
 @article{gabr_2015, title={Untitled}, volume={141}, ISSN={["1943-5606"]}, DOI={10.1061/(asce)gt.1943-5606.0001369}, number={8}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mo}, year={2015}, month={Aug} }
 @inproceedings{xiao_gabr_rahman_2014, title={Characterization of Structural Response of Two OCAES Vessel Configurations under Operational Loading}, booktitle={5th International Conference on Ocean Energy (ICOE)}, author={Xiao, Jinfu and Gabr, M.A. and Rahman, M.S.}, year={2014}, month={Nov} }
 @article{ahn_gabr_oh_shin_2014, title={Degraded secant modulus for permanent deformation of soils}, volume={16}, ISSN={1029-8436 1477-268X}, url={http://dx.doi.org/10.1080/10298436.2014.943208}, DOI={10.1080/10298436.2014.943208}, abstractNote={Two constitutive models, one with five parameters and the other with three parameters, were proposed for use in the prediction of permanent deformation of geotechnical materials under repetitive loading. The proposed model can be used with numerical tools such as the finite element method with equivalent linear analysis. The degraded secant modulus model with five parameters may employ the parameters of the material models widely accepted in pavement engineering practice to analyse to more general soil problems. The model parameters of the three-parameter model can be estimated based on the results of cyclic triaxial tests or by conducting inverse analysis based on the results of large-scale plate load tests, which are addressed and exemplified in detail in this article.}, number={6}, journal={International Journal of Pavement Engineering}, publisher={Informa UK Limited}, author={Ahn, Jaehun and Gabr, Mohammed and Oh, Jeongho and Shin, Hosung}, year={2014}, month={Sep}, pages={549–558} }
 @article{khalilzad_gabr_hynes_2014, title={Effects of Woody Vegetation on Seepage-Induced Deformation and Related Limit State Analysis of Levees}, volume={14}, ISSN={["1943-5622"]}, DOI={10.1061/(asce)gm.1943-5622.0000304}, abstractNote={AbstractWork in this paper investigates the effects of woody vegetation on soil hydraulic conductivity and the related probability of exceeding deformation-based performance limit states. A summary of results obtained from laboratory and field hydraulic conductivity tests for four levee sites is presented. Limit states, as defined based on the framework of critical state soil mechanics, are developed and simple probability analyses are used to quantify the probability of exceedance under hydraulic loading. A case study of Elkhorn Levee near Sacramento, California, is presented to demonstrate the applicability of the limit states concept. The field and laboratory hydraulic conductivity data obtained from the four levee test sites show no clear trend to support the notion that woody vegetation leads to either high or low values of hydraulic conductivity; site-specific testing is needed to discern such an effect. Even though the levee case used in this study (Elkhorn) was in a marginal condition of stability...}, number={2}, journal={INTERNATIONAL JOURNAL OF GEOMECHANICS}, publisher={American Society of Civil Engineers (ASCE)}, author={Khalilzad, Mahdi and Gabr, M. A. and Hynes, Mary Ellen}, year={2014}, month={Apr}, pages={302–312} }
 @inproceedings{aghazadeh_rahman_gabr_2014, title={Evaluation of plate anchors capacity in saturated soils using different constitutive models}, DOI={10.1115/omae2014-24226}, abstractNote={Evaluation of the uplift capacity of plate anchors in saturated clay is an important aspect in offshore anchoring of various structures. In most of the literature reviewed, a constitutive model such as Tresca or Mohr-Coulomb has been used in analyses. There exists a need to study the anchors’ pull out capacity using other advanced soil models and discern differences in results.}, booktitle={33rd International Conference on Ocean, Offshore and Arctic Engineering, 2014, vol 3}, author={Aghazadeh, Z. and Rahman, M. S. and Gabr, Mohammed}, year={2014} }
 @inproceedings{gabr_park_2014, title={Network Level Data Collection for Asset Management of Bridge Approach Slabs}, volume={234}, DOI={10.1061/9780784413272.329}, abstractNote={Asset management is a relatively new concept in geotechnical engineering. In general, the nature of performance data and response of structures within the realm of geotechnical engineering render the concept of asset management a valuable tool that, if effectively implemented, can lead to increased operation efficiency and cost control. Work in this paper focuses on comparing two network-level approaches for collection of data related to settlement of bridge approach slabs. These two approaches are the use of LiDAR scans and deformation profilometer. International roughness index (IRI) values and riding number (RN) values are used as output indicators of the quality of data collected in the field. Results demonstrate aspects of data collection on a network level of the bridge approach slab and summarize important features of the two approaches and data manipulation.}, booktitle={Geo-Congress 2014 Technical Papers}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A. and Park, Young Jin}, year={2014}, month={Feb}, pages={3383–3392} }
 @article{bahador_evans_gabr_2014, title={Numerical studies on the effect of temperature on the unsaturated hydraulic response of geotextiles}, volume={59}, DOI={10.1016/j.compgeo.2014.03.010}, abstractNote={A series of coupled thermo-hydraulic simulations were performed on a soil–geotextile column to understand the effect of temperature on suction distribution throughout the soil column and on the hydraulic performance of the geotextile as a drainage/capillary barrier layer. Two different constant temperatures of 0 °C and 38 °C and a temperature gradient of 4 °C along the column were modeled. Changing the temperature from 0 °C to 38 °C did not have a significant effect on the suction head distribution in the soil–geotextile column. The temperature gradient resulted in appreciable thermal vapor flow and changes in suction head and hydraulic conductivity of the geotextile. During drainage, the temperature gradient and lower temperature at the top of the column increased suction in the geotextile and its ability to function as a capillary barrier. During capillary rise, the temperature gradient and lower temperature at the top of the column decreased the suction in the geotextile and its ability to function as a capillary barrier. Changing the direction of the thermal gradient reversed the water vapor flow direction and its effect on the suction in the geotextile. A temperature gradient did not have a noticeable effect on the suction head of the geotextile when positive pore pressure was developed in the geotextile and adjacent soil during drainage.}, journal={Computers and Geotechnics}, publisher={Elsevier BV}, author={Bahador, M. and Evans, T.M. and Gabr, M.A.}, year={2014}, month={Jun}, pages={161–170} }
 @article{cowell_pyo_gabr_borden_kim_2014, title={Performance Assessment of Geosynthetics and Cement as Subgrade Stabilization Measures}, volume={37}, ISSN={0149-6115}, url={http://dx.doi.org/10.1520/GTJ20120206}, DOI={10.1520/gtj20120206}, abstractNote={Work in this paper presents the results of field testing on four instrumented roadway sections constructed on poor subgrade soils and stabilized with select fill, geosynthetics, or cement. Loading was applied using 1000 consecutive truck passes and profile surveying was performed to provide permanent deformation (rutting) data. Peak vertical stresses at the subgrade as well as moisture conditions were also monitored during testing. Results indicated that the deep undercut (31 in./790 mm) with select material backfill section produced the largest cumulative rut depths due to shallow incremental plastic strains induced during each axle pass. The use of a thin Aggregate Base Course (ABC) surface layer (3 in./75 mm) over the select material reduced the rate of rutting. The biaxial geogrid and the high strength geotextile showed a relatively equal performance in all aspects of the study. The cement stabilized section produced a slightly larger average rut depth than the geosynthetically-reinforced sections due to localized areas of pronounced cumulative rutting. However, there were several areas of the soil-cement test section that performed as well as the geosynthetically-reinforced sections.}, number={3}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Cowell, Tim and Pyo, Sangchul and Gabr, Mohammed A. and Borden, Roy H. and Kim, K. J.}, year={2014}, month={Mar}, pages={20120206} }
 @inproceedings{xiao_gabr_rahman_2014, title={Preliminary Structural Design of OCAES Vessel}, DOI={10.1115/omae2014-24053}, abstractNote={A vessel for Offshore Compressed Air Energy Storage (OCAES) is being considered as a part of the emerging technology to store intermittently generated energy from offshore renewable sources. The basic idea is to submerge the storage vessel into the ocean at a large water depth, convert the energy into compressed air, store it with using the hydrostatic water pressure to balance the compressed air pressure without requiring the storage vessels to resist high internal air pressure. An additional advantage is that the interface of air and water acts as a piston to maintain the air pressure level.}, booktitle={Volume 9B: Ocean Renewable Energy}, publisher={ASME International}, author={Xiao, Jinfu and Gabr, M. and Rahman, M. S.}, year={2014}, month={Jun} }
 @inproceedings{kebede_gabr_kayser_2014, title={Scour Zone Characterization by Deep Impinging Jet}, DOI={10.1115/omae2014-24257}, abstractNote={Scour downstream of many hydraulic structures such as culverts and spillways may be treated as analogues to jet scour. This study presents the characterization of a fluidized zone by an impinging jet using a recently developed In Situ Erosion Evaluation Probe (ISEEP). Jet embedment was varied from 0.61 m (2 ft) to 2.43 m (8 ft) in the laboratory with a jet velocity ranging from 3 m/s to 6 m/s using an external pump. A number of piezometers were installed radially and with depth around the probe to characterize the extent of the fluidized zone (zone where effective stress reaches zero). Results indicated that the shape of the embedded fluidized zone changes from spherical to elliptical with increasing impinging distance. The nature of the zone expansion was categorized into three phases: initial, transition, and steady state. A jet velocity of 3.8 m/s resulted in a lateral distance of the fluidization zone that extended 0.3 m from the probe. At jet velocities of 4.2 m/s and 4.5 m/s, the lateral distance of the fluidization zone reached about 0.40 m and 0.45 m, respectively. Vertically, a jet velocity of 4.2 m/s fluidized the soil up to 0.3 m above the jet (probe tip) at 2.4 m embedment depth. At an embedment depth of 2.4 m, this maximum fluidization zone occurs as a closed fluidization. The dimensions of this zone are a function of the applied jet velocity (considering the values used in this study).}, booktitle={Volume 8B: Ocean Engineering}, publisher={ASME International}, author={Kebede, Yulian A. and Gabr, Mohammed A. and Kayser, Mohammad F.}, year={2014}, month={Jun} }
 @article{gabr_borden_denton_smith_2013, title={An Insertion Rate Model for Pile Installation in Sand by Jetting}, volume={37}, ISSN={0149-6115}, url={http://dx.doi.org/10.1520/GTJ20120191}, DOI={10.1520/gtj20120191}, abstractNote={The use of jetting is an approach to aid the installation of piles, especially in areas that have hard but relatively shallow subsurface soil layers. Jetting piles for a portion of their installation depth minimize their exposure to excessive driving stress and provide energy savings and noise reduction. However, the literature offers little information regarding the appropriate selection of jetting parameters, such as flow rate and jet velocity, which are needed to produce the desired installation times as a function of soil strength. This paper presents a model for estimating pile jetting parameters based on the results from laboratory and field testing. The model is based on an idealization of the applied shear stress that is produced by the jet as well as the soil resistance to pile insertion. The model is applied to 19 field installations where the jetted depths of the piles range from 10–34 ft. The field data yield ratios of 6–20 for the jet flow rate (Qw) to the rate of the pile volume insertion in terms of time (Qp), with the lower ratios associated with higher jet velocities. The proposed model yields an estimated Qw/Qp that is within +/− 20 % of the measured values.}, number={1}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Gabr, M. A. and Borden, Roy H. and Denton, R. L. and Smith, Alex W.}, year={2013}, month={Oct}, pages={20120191} }
 @article{gabr_caruso_key_kayser_2013, title={Assessment of In Situ Scour Profile in Sand Using a Jet Probe}, volume={36}, ISSN={0149-6115}, url={http://dx.doi.org/10.1520/GTJ20120046}, DOI={10.1520/gtj20120046}, abstractNote={Abstract}, number={2}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Gabr, Mo and Caruso, Cary and Key, Austin and Kayser, Mohammad}, year={2013}, month={Jan}, pages={20120046} }
 @inproceedings{kayser_gabr_2013, title={Assessment of Scour Potential of Silty Sand Using ISEEP}, booktitle={Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering}, author={Kayser, M. and Gabr, M.}, year={2013}, month={Sep} }
 @article{kayser_gabr_2013, title={Assessment of Scour on Bridge Foundations by Means of In Situ Erosion Evaluation Probe}, volume={2335}, ISSN={["2169-4052"]}, DOI={10.3141/2335-08}, abstractNote={ The work in this paper presents the use of an in situ erosion evaluation probe (ISEEP) to assess scour depth at bridge piers. Numerical modeling and deployment of the device at a North Carolina Outer Banks site damaged by Hurricane Irene in 2011 demonstrates the applicability of the proposed concept. Computational fluid dynamics software, FLOW-3D, was used to assess the scour depth at a bridge pier, and the results were compared with values based on ISEEP-estimated parameters by using an excess-stream power model. The scour depth was also calculated from empirical equations that assumed the same conditions as those used in the numerical analysis. Parametric analysis using FLOW-3D indicated that of the parameters for defining the scour depth, the entrainment coefficient had the largest effect, whereas the drag coefficient had the smallest effect on the scour magnitude within the range of values included in this analysis. The estimated scour depths that were based on ISEEP data agreed relatively well with the scour magnitudes obtained from the numerical analysis, as the ISEEP data reflected the changes in the properties of the sand layer with depth. In contrast, the scour magnitude calculated from the empirical equations underestimated the scour depth, mainly because these equations had no provision for a layered-soil profile. Further validation of both the field-testing procedure and the data reduction approach, including the assessment of the applicability in soils that contain an appreciable percentage of fines, is recommended. }, number={2335}, journal={TRANSPORTATION RESEARCH RECORD}, publisher={Transportation Research Board}, author={Kayser, Mohammad and Gabr, Mohammed A.}, year={2013}, pages={72–78} }
 @article{gabr_xia_rahman_evans_2013, title={Geotechnical Aspects of OCAES Vessel and Anchoring System}, volume={19}, number={3}, journal={GEOSTRATA, American Society of Civil Engineering (ASCE)}, author={Gabr, M.A. and Xia, JinFu and Rahman, Shamim and Evans, T.M.}, year={2013}, month={Jun} }
 @article{bahador_evans_gabr_2013, title={Modeling Effect of Geocomposite Drainage Layers on Moisture Distribution and Plastic Deformation of Road Sections}, volume={139}, ISSN={["1943-5606"]}, DOI={10.1061/(asce)gt.1943-5606.0000877}, abstractNote={AbstractThe effect of geosynthetic layers on moisture distribution and plastic deformation of paved and unpaved road sections is studied using numerical simulations. The geosynthetic layers consisted of, from top to bottom, a transport layer, a geonet, and a nonwoven geotextile (referred to as a geocomposite capillary barrier drain by previous researchers). Two geotextile types were modeled as the transport layer: woven fiberglass and nonwoven polypropylene. The numerical models were verified against published results obtained from a soil-geotextile column. Inclusion of the geosynthetic layers at the interface of the aggregate base course (ABC) and subgrade increased suction in the subgrade and decreased it in the ABC during a simulated rainfall event. The woven fiberglass geotextile led to higher suctions in the ABC compared with the nonwoven polypropylene geotextile. The geosynthetic layers decreased the plastic deformation in both paved and unpaved road sections through combined mechanistic and hydraul...}, number={9}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, publisher={American Society of Civil Engineers (ASCE)}, author={Bahador, M. and Evans, T. M. and Gabr, M. A.}, year={2013}, month={Sep}, pages={1407–1418} }
 @article{cote_robinson_gabr_borden_2013, title={Performance-Cost Analysis of Stabilized Undercut Subgrades}, volume={139}, ISSN={["0733-9364"]}, DOI={10.1061/(asce)co.1943-7862.0000572}, abstractNote={AbstractAn approach for comparatively evaluating the performance cost of undercut subgrade stabilization measures is presented. The performance-cost analysis coupled results from laboratory cyclic load testing with material prices and estimated cost factors for stabilization alternatives. The study utilized data from 22 simulated undercut sections with different stabilization configurations over a soft subgrade with a California bearing ratio of approximately 2.0%. The computed cost factors are normalized with respect to the rut-depth magnitude and subgrade strength. Sections with lime-stabilized subgrade were the most economical with respect to initial and postrut repair cycles. Unreinforced aggregate based course (ABC) sections between 356 and 508 mm (14 and 20 in.) in thickness were economical during initial cycles. Sections with geosynthetic reinforcement showed that once enough rut depth is induced to mobilize the strength of the reinforcement, economical performance was comparable with other stabili...}, number={2}, journal={JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT-ASCE}, publisher={American Society of Civil Engineers (ASCE)}, author={Cote, Benjamin and Robinson, Brent and Gabr, M. A. and Borden, Roy H.}, year={2013}, month={Feb}, pages={121–127} }
 @article{robinson_suarez_gabr_kowalsky_2012, title={Configuration Optimization of Drilled Shafts Supporting Bridge Structures: Three Case Studies}, volume={17}, ISSN={1084-0680 1943-5576}, url={http://dx.doi.org/10.1061/(asce)sc.1943-5576.0000118}, DOI={10.1061/(asce)sc.1943-5576.0000118}, abstractNote={A common approach to estimating the point of fixity is to utilize the results of a single pile lateral analysis. Although no universal agreement exists as to the definition of the location of the point of fixity, it is generally accepted that its location will affect the computed stresses and displacements of a bridge structure. This study summarizes a method to determine a cantilever’s equivalent length of drilled shaft foundation elements supporting a bridge. Results from an equivalent frame model are compared to those for bents modeled using the finite element method and nonlinear soil models for three bridges in North Carolina. Results indicated that the equivalent frame model provides responses that are comparable to those obtained from more rigorous finite element analyses. The study presents the results of the optimization of the support system by reducing the number, or size, of the shafts while maintaining an acceptable level of safety.}, number={3}, journal={Practice Periodical on Structural Design and Construction}, publisher={American Society of Civil Engineers (ASCE)}, author={Robinson, Brent and Suarez, Vinicio and Gabr, Mohammed and Kowalsky, Mervyn}, year={2012}, month={Aug}, pages={93–101} }
 @article{gabr_sharmin_quaranta_2012, title={Multiphase Extraction of Light Non-aqueous Phase Liquid (LNAPL) Using Prefabricated Vertical Wells}, volume={31}, ISSN={0960-3182 1573-1529}, url={http://dx.doi.org/10.1007/s10706-012-9567-5}, DOI={10.1007/s10706-012-9567-5}, number={1}, journal={Geotechnical and Geological Engineering}, publisher={Springer Science and Business Media LLC}, author={Gabr, M. A. and Sharmin, N. and Quaranta, J. D.}, year={2012}, month={Oct}, pages={103–118} }
 @article{sharmin_gabr_2012, title={Optimized prefabricated vertical wells (PVWs) for LNAPL recovery}, volume={49}, number={12}, journal={Canadian Geotechnical Journal}, author={Sharmin, N. and Gabr, M. A.}, year={2012}, pages={1343–1443} }
 @article{sharmin_gabr_2012, title={Optimized prefabricated vertical wells for light nonaqueous phase liquid recovery}, volume={49}, ISSN={["0008-3674"]}, DOI={10.1139/t2012-097}, abstractNote={Work presented herein examines optimization of prefabricated vertical well (PVW) performance during the extraction of light nonaqueous phase liquids (LNAPLs) in liquid and vapor phases in terms of ...}, number={12}, journal={CANADIAN GEOTECHNICAL JOURNAL}, publisher={Canadian Science Publishing}, author={Sharmin, N. and Gabr, M. A.}, year={2012}, month={Dec}, pages={1434–1443} }
 @article{park_gabr_robinson_borden_2012, title={Subgrade Undercut Criteria Based on Modeling of Rutting and Pumping Response}, volume={138}, ISSN={1090-0241 1943-5606}, url={http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0000695}, DOI={10.1061/(asce)gt.1943-5606.0000695}, abstractNote={AbstractThe stability of subgrade soils is a major concern during roadway construction with inappropriately soft layers often undercut and replaced by competent or stabilized materials. Systematic undercut criteria are established using numerical modeling with varying the strength and stiffness parameters of the subgrade and representing the mechanistic behavior as an elastic-perfectly plastic medium. Two modes of domain configurations were considered: the plane strain and axisymmetric conditions. The plane strain mode is assumed to simulate proof roller loading with four parallel tires and mainly provides information about excessive pumping response as materials at deeper layers are affected. The axisymmetric mode provides information related to excessive rutting and is used to simulate the effect of single or dual tires representing construction traffic, rather than a series of closely spaced axle loads. Undercut criteria are proposed for meeting a deformation limit state of 25 mm for both pumping and r...}, number={10}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Park, Young Jin and Gabr, Mohammed A. and Robinson, Brent R. and Borden, Roy H.}, year={2012}, month={Oct}, pages={1175–1184} }
 @inproceedings{khalilzad_gabr_2011, title={Deformation-Based Limit States for Earth Embankments}, volume={211}, DOI={10.1061/41165(397)372}, abstractNote={Traditional design approaches based on the concept of factor of safety do not provide a complete indicator of level of safety pertinent to earth structures given uncertainties in loading, soil properties, and changes in geometry that can take place with time. Thus, there has been a tendency to utilize probabilistic analysis in addition to conventional design methods. Work is presented herein to introduce limit states, based on numerical modeling in conjunction with probabilistic analysis, for water holding embankments and flood protection structures. An embankment dam was modeled using coupled flow/deformation analysis to capture the interdependency of under-seepage and through-seepage with deformation associated with the development of plastic zones and shear bands. Limit states were defined in terms of deformations and seepage gradients that correspond to levels of performance or extent of damage in the embankment. The analysis showed as the water level increased in the reservoir, lateral displacement also increased and zones with high seepage velocity emerged at the entrance and exit locations of the dam. Depending on the statistical variation of input parameters, probabilities of exceeding limit states are calculated and presented for the case study. As water rises in the pool, the probability of exceeding each limit state increased and the target deformation was changed to the next limit state.}, booktitle={Geo-Frontiers 2011}, publisher={American Society of Civil Engineers (ASCE)}, author={Khalilzad, M. and Gabr, M. A.}, year={2011}, month={Mar}, pages={3639–3648} }
 @inproceedings{khalilzad_gabr_2011, title={External Stability of Geotubes Subjected to Wave Loading}, volume={224}, DOI={10.1061/41183(418)114}, abstractNote={Geotubes used as shoreline protective structures are formed using geotextile material that is hydraulically filled with soil to form desired dimensions. Historically, these structures are mainly used in the US for the dewatering of wet soils, and there is a focus in the literature on the internal stability aspects where filling pressure is specified such that rupture does not occur. After the 2008 Hurricane Ike hit on Galveston, failure of geotubes was observed in differential lateral displacement and rotation modes as well as due to the scour of the underlying foundation soil. External stability of geotubes is studied in this paper considering the effects of wave loading with the rising water level due to the storm surge. Results indicated that limit equilibrium analysis yielded factors of safety less than unity, yet, in some cases functionality is preserved as the lateral deformation can be tolerated and the height of the structure is maintained. Based on the parameters assumed in this paper performance aspects can be preserved during storm loading if the soil used to form the geotube is engineered to have soil elasticity modulus more than 1 MPa, and soil unit weight higher than 18 kN/m 3 . At these values, the geotube exhibited the attributes of a rigid body response, with a minimal distortion of shape under the applied loading.}, booktitle={Georisk 2011}, publisher={American Society of Civil Engineers (ASCE)}, author={Khalilzad, M. and Gabr, M. A.}, year={2011}, month={Jun}, pages={1044–1054} }
 @inproceedings{bahador_evans_gabr_2011, title={Geotextile Drains in Road Sections Subjected to Unsaturated Conditions}, volume={211}, DOI={10.1061/41165(397)190}, abstractNote={In many cases, the intrusion of water (either through rainfall or capillary rise) into the subgrade or aggregate base course in road sections can result in the swelling of the subgrade, decreasing the effective stress and, consequently, the shear strength. To mitigate these adverse conditions, a geotextile drain (GD) can be introduced to intercept upward and downward water flow and divert it towards edge drains, with flow induced under unsaturated conditions. Design of this type of system for the general case of partial saturation, however, is significantly complicated by the significant scale differences in the spatial extent and hydraulic properties of the soil and geotextile layers. In this paper, a road section consisting of aggregate base course (ABC) and subgrade is modeled using the finite element program SIGMA/W. Results show that the suction head in the subgrade and the air entry value of the GD have important effects on downward water flow into the subgrade. Low air entry value geotextiles cause a decrease in suction above the GD leading to a decrease in shear strength and increase in deformation. Guidelines are presented for the efficient design of GD as capillary barriers in roadways to minimize intrusion of water into the subgrade and ABC.}, booktitle={Geo-Frontiers 2011}, publisher={American Society of Civil Engineers (ASCE)}, author={Bahador, Mahdi and Evans, T. Matthew and Gabr, M. A.}, year={2011}, month={Mar}, pages={1862–1871} }
 @inproceedings{caruso_gabr_2011, title={In Situ Assessment of Scour Potential with Depth Using Jetting Approach}, volume={211}, DOI={10.1061/41165(397)152}, abstractNote={A vertical probe (VP) employing a water jet has been developed for assessing scour potential and erosion rates of sediments typically found at the bottom of rivers or streams. The probe for "In situ Evaluation of Scour Potential (ISEP)" is based on the idea that analysis of the probe penetration rate into the soil correlates with scour rate and erosion potential. The method discussed herein aims at measuring the potential scour rate in situ and as a function of depth. Scour rates determined with this method at shallow depths are found in agreement with values published for similar sands. Results presented herein show high erosion rates in the near surface for all velocities tested (water velocities varying between 0.5 m/s to 5.8 m/s). As the probe moved deeper into the soil, the erosion rate dropped rapidly for all water velocities tested. These results, being consistent with previously published results, support the utility of this technique for quickly assessing scour hazards.}, booktitle={Geo-Frontiers 2011}, publisher={American Society of Civil Engineers (ASCE)}, author={Caruso, Cary and Gabr, Mohammed}, year={2011}, month={Mar}, pages={1483–1492} }
 @article{kunberger_gabr_2011, title={Laboratory testing and microanalysis of colloidal mobilization from a glacial till}, volume={48}, ISSN={["1208-6010"]}, DOI={10.1139/t11-030}, abstractNote={ The effect of the dispersion and piping of clay fines — colloid mobilization — as a means of remediating subsurface contamination was investigated. Prior colloid mobility research has focused on mitigating colloidal movement to reduce contaminant transport or monitoring colloids to determine the extent of mobility and contamination transport. To date, limited work has been performed to evaluate remediation efficiency associated with the removal of clay-sized (colloidal) particles and related sorbed contamination. Laboratory flow-through tests were performed on a glacial till from a radioactive cesium contaminated site. Post-testing analysis comprised mass balance checks, grain-size distribution testing, and microscopic analysis of removed particles. Results showed the potential of initiating and maintaining clay dispersion and piping, thus establishing a means to mobilize colloids and subsequently remove them from the subsurface environment. Beneficial effects of hydraulic gradient and ionic strength manipulations were influenced by soil properties, such as cation exchange capacity, clay content, and average pore diameter. In general, colloid mobilization testing results found that extreme levels of mobilization typically resulted in particle trapping and an overall reduction in colloidal removal, while the effect of more moderate levels was mobilization with increased rates of removal. }, number={7}, journal={CANADIAN GEOTECHNICAL JOURNAL}, publisher={Canadian Science Publishing}, author={Kunberger, T. and Gabr, M. A.}, year={2011}, month={Jul}, pages={1116–1124} }
 @inproceedings{evans_ning_gabr_2011, title={Sensors, Monitoring, and Health Assessment in the Undergraduate Curriculum}, volume={211}, DOI={10.1061/41165(397)180}, abstractNote={Currently, the use of advanced sensing technologies is rapidly increasing in research and practice, but the implementation of sensors and health monitoring of earth structures in the undergraduate curriculum has not kept pace with advances in the state of practice. This paper introduces the development of educational modules based upon the installation of a remotely-monitored sensor network. The modules will expose students in geotechnical engineering to advanced sensor technologies and opportunities to observe and analyze data that are collected in real time. Initial assessments indicate that introduction of even basic concepts on sensors increases student comprehension and confidence on the subject.}, booktitle={Geo-Frontiers 2011}, publisher={American Society of Civil Engineers (ASCE)}, author={Evans, T. Matthew and Ning, Zhangwei and Gabr, Mohammed A.}, year={2011}, month={Mar}, pages={1763–1773} }
 @article{robinson_suarez_gabr_kowalsky_2011, title={Simplified Lateral Analysis of Deep Foundation Supported Bridge Bents: Driven Pile Case Studies}, volume={16}, ISSN={["1084-0702"]}, DOI={10.1061/(asce)be.1943-5592.0000182}, abstractNote={A simplified approach for modeling soil and foundation system supported bridge bents is applied to three bridges that represent three pile types and three superstructures. This point-of-fixity approach is applied by modeling the bridge bent substructure as an elastic frame. The models are compared with more refined analyses in FB-MultiPier, with SAP as an independent verification tool, using pile sections with nonlinear soil, pile, and pile cap material properties. The results for simple pile bents show that an equivalent frame model provides similar moment, shear, and displacement values as those obtained from both the SAP and MultiPier nonlinear analyses. Analysis results also indicated that the equivalent frame model parameters are particularly sensitive to the comparable selection of both axial and lateral loads. If lateral loads used to develop the equivalent model are higher than experienced, the axial and lateral deflections and moments will also be higher. For design purposes, this is conservative.}, number={4}, journal={JOURNAL OF BRIDGE ENGINEERING}, author={Robinson, Brent and Suarez, Vinicio and Gabr, Mohammed A. and Kowalsky, Mervyn}, year={2011}, pages={558–569} }
 @article{park_gabr_borden_2010, title={Discussion of "p-y Criterion for Rock Mass" by Robert Liang, Ke Yang, and Jamal Nusairat}, volume={136}, ISSN={["1943-5606"]}, DOI={10.1061/(asce)gt.1943-5606.0000171}, number={1}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, publisher={American Society of Civil Engineers (ASCE)}, author={Park, Y. J. and Gabr, M. A. and Borden, R. H.}, year={2010}, month={Jan}, pages={272–274} }
 @book{borden_cote_gabr_park_pyo_robinson_2010, title={Establishment of subgrade undercut criteria and performance of alternative stabilization measures, No. FHWA/NC/2008-07}, url={https://rosap.ntl.bts.gov/view/dot/18455}, note={No. FHWA/NC/2008-07).}, journal={North Carolina State University}, author={Borden, R.H. and Cote, B.M. and Gabr, M.A. and Park, Y.J. and Pyo, S.C. and Robinson, B.R.}, year={2010}, month={Aug} }
 @article{kim_ahn_han_gabr_2010, title={Experimental Evaluation of Strength Characteristics of Stabilized Dredged Soil}, volume={22}, ISSN={["0899-1561"]}, DOI={10.1061/(asce)mt.1943-5533.0000052}, abstractNote={A composite geomaterial (CGM) is developed using dredged soil, bottom ash, cement and air foam. The engineering properties of the CGM are characterized as a function of the content of the various admixtures and the curing time in a laboratory test program. Several series of unconfined compression tests were carried out to characterize the strength and elastic properties of the CGM. Experimental results indicate that the unconfined compressive strength and modulus of CGM are influenced by the content of each component in the mixture. The unconfined compressive strength of CGM increases with an increase in curing time due to the pozzolanic reaction of the bottom ash. The strength after 28 days of curing is found to be approximately 1.5–2.3 times the strength after 7 days of curing, regardless of mix conditions. The bottom ash materials contain nearly 50% siliceous material and 13.9% CaO. With the removal of particles larger than 4.75 mm, a larger surface area is available to react with cement. It is postula...}, number={5}, journal={JOURNAL OF MATERIALS IN CIVIL ENGINEERING}, publisher={American Society of Civil Engineers (ASCE)}, author={Kim, Yun Tae and Ahn, J. and Han, W. J. and Gabr, M. A.}, year={2010}, month={May}, pages={539–544} }
 @inproceedings{caruso_gabr_2010, title={In Situ Measurement of the Scour Potential of Non-Cohesive Sediments (ISEP)}, volume={211}, DOI={10.1061/41147(392)10}, abstractNote={A vertical probe (VP) employing a water jet has been developed for assessing scour potential and scour rates of sediments typically found at the bottom of rivers or streams. The probe termed "In situ Scour Evaluation Probe," or ISEP, is based on the idea that analysis of the probe penetration rate into the soil may be correlated with scour rate and erosion potential. The method proposed herein aims at measuring the potential scour rate in situ and as a function of depth. Results on the test sand with mean particle diameter (D50) ∼0.3 mm suggest that the rate of advancement of the probe can be empirically correlated to the vertical velocity of the water at the tip of the probe raised to a positive exponent. For the saturated sand used in testing, the exponent appears to be 1.4. The rate of probe advancement seems to also vary with moisture content. Thus far, scour rates determined with this proposed method are found to be in reasonable agreement with scour rates published for similar sand type.}, booktitle={Scour and Erosion}, publisher={American Society of Civil Engineers (ASCE)}, author={Caruso, Cary and Gabr, Mohammed}, year={2010}, month={Oct}, pages={115–125} }
 @article{suits_sheahan_cote_robinson_pyo_park_gabr_borden_2010, title={Laboratory Performance Comparison of Stabilized Undercut Subgrade Under Cyclic Loading}, volume={33}, DOI={10.1520/gtj102935}, abstractNote={Abstract}, number={6}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Suits, L. D. and Sheahan, T. C. and Cote, Benjamin and Robinson, Brent and Pyo, Sangchul and Park, Young Jin and Gabr, Mohammed and Borden, Roy}, year={2010}, pages={102935} }
 @article{vidot-vega_possiel_robinson_kowalsky_gabr_2009, title={Evaluation of Rotational Stiffness of Elastomeric Bearing Pad-Anchor Bolt Connections on Deep Foundation Bents}, volume={14}, ISSN={["1084-0702"]}, DOI={10.1061/(ASCE)BE.1943-5592.0000010}, abstractNote={Experimental tests are performed on a bearing pad-anchor bolt connection to study rotational stiffness and moment transfer capabilities of a typical bridge configuration. The experimental program is divided in two phases. The first phase consisted of shear and compression properties of two types of bearing pads. The second phase consisted of a total of 42 full-scale tests of a bearing pad-anchor bolt connection. The tested bridge-bent configuration includes two AASHTO Type II girders made continuous with a slab and diaphragm, bearing pads, pile caps, and piles. Variables included axial loads applied to the piles and bearing pads, two different sets of bearing pads, and three different pile types. The bridge connection is subjected to lateral cyclic reversed loading in one-cycle displacement increments. Test results show the potential for this type of connection to sustain lateral loads and flexural moments, and to develop the full strength of the pile elements. Shear and compression modulus are also obtained for the bearing pad types used in this study. Rotational stiffness values for the connection are determined as a function of varying axial loads.}, number={6}, journal={JOURNAL OF BRIDGE ENGINEERING}, publisher={American Society of Civil Engineers (ASCE)}, author={Vidot-Vega, Aidcer L. and Possiel, Ben and Robinson, Brent and Kowalsky, Mervyn J. and Gabr, Mohammed A.}, year={2009}, pages={487–495} }
 @article{ahn_cote_robinson_gabr_borden_2009, title={Inverse Analysis of Plate Load Tests to Assess Subgrade Resilient Modulus}, volume={2101}, ISSN={["2169-4052"]}, DOI={10.3141/2101-13}, abstractNote={ Cyclic plate load testing is commonly used to investigate subgrade response under repetitive loads. Two frameworks for performing inverse analysis are described for backcalculating resilient moduli on the basis of measured key outputs. In the first approach, an elastic modulus is back-calculated in each selected domain; in the second, selected parameters in the resilient modulus model are estimated. The axisymmetric finite element model analysis results suggest that the second approach is more robust because it allows the modulus to be distributed in the selected domain. A series of sensitivity analyses was conducted with the second approach to illustrate how the assumed properties or model geometry affects the backcalculated parameters. Discrepancies between the back-calculated parameters and their known values were observed when the distance to the boundary–-that is, the radial distance from centerline to sidewall–-was not properly assigned. When backcalculating only selected parameters in the resilient modulus equation, it is necessary to assign the other parameters carefully (i.e., from laboratory tests or references). An example analysis shows the application of the proposed approach to an actual plate load test. }, number={2101}, journal={TRANSPORTATION RESEARCH RECORD}, publisher={Transportation Research Board}, author={Ahn, Jaehun and Cote, Benjamin M. and Robinson, Brent and Gabr, Mohammed A. and Borden, Roy H.}, year={2009}, pages={110–117} }
 @inbook{gabr_akram_2009, title={Sample Preparation Techniques for Filtration Testing of Fly Ash with Nonwoven Geotextiles}, url={http://dx.doi.org/10.1520/stp16586s}, DOI={10.1520/stp16586s}, abstractNote={A laboratory investigation was conducted to evaluate the applicability of five preparation techniques of fly ash/geotextile specimens for the gradient ratio (GR) test (ASTM D 5101-90). These techniques included the current ASTM method, a modified ASTM method, a vibro-prep technique, a dry preparation, and slurry method. Using the ASTM method for preparation, measured specific discharge and GR across the fly ash-geotextile systems were 8.0×10-4 cm/sec and 1.25, respectively. However, during the placement of the fly ash in the permeameter some intrusion of the particles into the geotextile openings took place. A technique for placing fly ash in the permeameter was modified after ASTM D5101. Using this modified method, the specific discharge and GR were measured to be 6.8x10-4 cm/sec and 0.80, respectively. The specimens prepared using the slurry method exhibited a relatively stable behavior. The specific discharge had an average value of 2.5×10-4 cm/sec after 600 hours of testing. The GR decreased from 1.52 to 1.37 during this period. The extent of piping under different testing conditions was quantified in this investigation. The specimens prepared using dry method exhibited an unsteady behavior and piping was observed to be dominant. Although piping of fine particles through the geotextile system was less than the suggested limit of 0.25 g/cm2 for soils, it is proposed that in the case of fly ash specimens with geotextile, stable systems should be categorized as those with piping rate less than 0.03 g/cm2.}, booktitle={Sampling Environmental Media}, publisher={ASTM International}, author={Gabr, MA and Akram, MH}, year={2009}, month={Mar}, pages={376–376-13} }
 @article{hossain_gabr_asce_2009, title={The effect of shredding and test apparatus size on compressibility and strength parameters of degraded municipal solid waste}, volume={29}, ISSN={["0956-053X"]}, DOI={10.1016/j.wasman.2009.03.024}, abstractNote={In many situations, MSW components are processed and shredded before use in laboratory experiments using conventional soil testing apparatus. However, shredding MSW material may affect the target property to be measured. The objective of this study is to contribute to the understanding of the effect of shredding of MSW on the measured compressibility and strength properties. It is hypothesized that measured properties can be correlated to an R-value, the ratio of waste particle size to apparatus size. Results from oedometer tests, conducted on 63.5 mm, 100 mm, 200 mm diameter apparatus, indicated the dependency of the compressibility parameters on R-value. The compressibility parameters are similar for the same R-value even though the apparatus size varies. The results using same apparatus size with variable R-values indicated that shredding of MSW mainly affects initial compression. Creep and biological strain rate of the tested MSW are not significantly affected by R-value. The shear strength is affected by shredding as the light-weight reinforcing materials are shredded into smaller pieces during specimen preparation. For example, the measured friction angles are 32° and 27° for maximum particle sizes of 50 mm and 25 mm, respectively. The larger MSW components in the specimen provide better reinforcing contribution. This conclusion is however dependent on comparing specimen at the same level of degradation since shear strength is also a function of extent of degradation.}, number={9}, journal={WASTE MANAGEMENT}, publisher={Elsevier BV}, author={Hossain, M. S. and Gabr, M. A. and Asce, F.}, year={2009}, month={Sep}, pages={2417–2424} }
 @inproceedings{hossain_gabr_haque_2008, title={Deformation of MSW Bioreactor Landfills: Properties and Analysis Approach}, volume={177}, DOI={10.1061/40970(309)27}, abstractNote={Bioreactor landfills are operated for rapid stabilization of waste, increased landfill gas generation for cost-effective energy recovery, increase in landfill space, enhanced leachate treatment, and reduced post closure maintenance period. Due to rapid stabilization and settlement of solid waste, bioreactor landfills are gaining popularity as an alternative to conventional Subtitle D landfills. However, the addition of leachate to accelerate waste decomposition changes the physical and engineering characteristics of Municipal Solid Waste (MSW), which affects the compressibility and shear strength behavior of MSW. Settlement during the active landfilling period is beneficial as it increases the landfill capacity, however, large differential settlement may cause serious damage to the existing leachate recirculation pipe system and interim covers. Also, due to accelerated decomposition and changes in shear strength properties, the stability of landfill slopes is expected to be affected. The objective of this paper is to analyze the compressibility of MSW in a bioreactor landfill as a function of construction sequence, time and waste placement using the finite element program PLAXIS. In this analysis, the layer properties are adjusted to account for extent of decomposition. The results from PLAXIS are compared with waste settlement data collected during the filling of a landfill cell at Calgary Biocell in Canada.}, booktitle={GeoCongress 2008}, publisher={American Society of Civil Engineers (ASCE)}, author={Hossain, Sahadat and Gabr, Mohamed A. and Haque, Mohamed A.}, year={2008}, month={Mar}, pages={216–223} }
 @article{sharmin_kunberger_gabr_quaranta_bowders_2008, title={Performance modeling and optimization of contaminant extraction using prefabricated vertical wells (PVWs)}, volume={15}, ISSN={["1751-7613"]}, DOI={10.1680/gein.2008.15.3.205}, abstractNote={ Well injection depth extraction (WIDE) is a hybrid in situ subsurface remediation technology applicable for liquid and gas extraction in fine-grained soils. A finite element model is developed to study the impact of the extraction process, using WIDE, on the groundwater head distribution and contaminant transport. An optimization process is employed to develop an operating schedule to control groundwater elevations and therefore improve removal efficiency of a given contaminant phase. The model results showed that groundwater elevation was lowered at the rate of approximately 30 mm/h at an extraction rate of 0.125 m3/h. The transport model is analyzed for three scenarios: (1) applying a continuous source of benzene concentration to provide information on the required time for mobilization of benzene due to the presence of a constant source at the top of the water table; (2) applying an initial pulse concentration of benzene at the top of the groundwater table to show the reduction rate of soluble benzene concentration with time, once the liquid free product is removed, and the soluble phase is removed from within the sand seam but remains above it in the lower-permeability layer; and (3) applying a uniform distribution of the soluble phase of benzene within the geologic medium between the wells to investigate progressive contaminant removal from the hydro-geologic domain, given that groundwater is contaminated with soluble phase. Effluent concentration equal to the initially assumed constant source of 0.3 mg/L of benzene leaking into a 0.08 m thick sand lens was obtained after 18 h of system operation. On the other hand, once the source ceased to exist, and considering an initial pulse concentration of benzene on top of the groundwater level, 125 h of continuous system operation was needed to lower the benzene concentration to less than 0.005 mg/L (maximum concentration level for drinking water standards) within the flow domain. Results from the optimization study showed that an operation schedule of 3 h ‘on’ and 21 h ‘off’ can enhance the efficiency of WIDE extraction of subsurface contaminants in various phases. }, number={3}, journal={GEOSYNTHETICS INTERNATIONAL}, publisher={Thomas Telford Ltd.}, author={Sharmin, N. and Kunberger, T. and Gabr, M. A. and Quaranta, J. D. and Bowders, J. J.}, year={2008}, month={Jun}, pages={205–215} }
 @inproceedings{gabr_borden_smith_denton_eggleston_broome_2008, title={Sustainability In coastal construction: Characterization and ecological impact of jetting-induced disturbance zones}, booktitle={New Horizons in Geotechnical and Geoenvironmental Engineering, Tanta University, Egypt, September 2008}, author={Gabr, M. A. and Borden, R. H. and Smith, A. W. and Denton, R. L. and Eggleston, D. B. and Broome, S. W.}, year={2008} }
 @inproceedings{robinson_suarez_robalino_kowalsky_gabr_2007, title={A Point of Fixity Model for Pile and Shaft Bents}, volume={158}, ISBN={9780784409022}, url={http://dx.doi.org/10.1061/40902(221)16}, DOI={10.1061/40902(221)16}, abstractNote={Pile bents are often used in bridge foundation systems. These sub- structural elements are constructed by installing a row of piles and connecting them with a concrete cap. A common design practice is to use a point of fixity approach which idealizes the soil-pile system as a cantilever of a particular length, forming a single column in an elastic frame. In this paper, current design practices are reviewed, and a new method for calculating point of fixity is developed for engineers who must consider separate single pile lateral analyses and elastic frame analyses. The proposed approach better matches the maximum moments and displacements obtained from non-linear analysis for a pile in the foundation system that is subjected to the lateral loading applied to the bridge. An example that compares a pile bent designed as an equivalent elastic frame with a nonlinear analysis is presented. Comparative results show the elastic frame model with two equivalent lengths (based on transverse and longitudinal loading conditions) satisfactorily matches results from nonlinear analysis, while a frame with a single point of fixity, based on deepest equivalent length, provides a conservative approximation of the nonlinear model.}, booktitle={Contemporary Issues In Deep Foundations}, publisher={American Society of Civil Engineers}, author={Robinson, Brent and Suarez, Vinicio and Robalino, Pablo and Kowalsky, Mervyn and Gabr, Mohammed}, year={2007}, month={Oct} }
 @article{gabr_2007, title={Erratum for “Shear Strength Parameters of Municipal Solid Waste with Leachate Recirculation” by M. A. Gabr, M. S. Hossain, and M. A. Barlaz}, volume={133}, DOI={10.1061/(asce)1090-0241(2007)133:9(1181)}, number={9}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A.}, year={2007}, month={Sep}, pages={1181–1181} }
 @article{cho_gabr_clark_borden_2007, title={Field P-y curves in weathered rock}, volume={44}, ISSN={["0008-3674"]}, DOI={10.1139/t07-026}, abstractNote={In weathered and decomposed rock profiles, the lack of an acceptable analysis procedure for estimating lateral load–displacement response of drilled shafts is compounded by the unavailability of weathered material properties, including the material's lateral subgrade reaction modulus. Such deficiency often leads to the overdesign of the drilled shaft foundation. Six field tests were conducted on drilled shafts to investigate the shape and magnitude of P–y curves in weathered rock material at three locations in North Carolina. The tested shafts were instrumented using dial gages, strain gages, and continuous vertical inclinometers. The measured load versus deflection data are used to study the stiffness response of weathered rock. Measured lateral responses are compared with the results estimated based on a "weak rock" model and a stiff clay model. The comparison shows that Reese's weak rock model overestimated the resistances of the tested shafts while the stiff clay model consistently underestimated the measured shaft resistances. The measured and computed results are analyzed and discussed.Key words: drilled shaft, weathered rock P–y curve, subgrade modulus, ultimate resistances in weathered rock, verification tests.}, number={7}, journal={CANADIAN GEOTECHNICAL JOURNAL}, publisher={Canadian Science Publishing}, author={Cho, Kook Hwan and Gabr, Mohammed A. and Clark, Shane and Borden, Roy H.}, year={2007}, month={Jul}, pages={753–764} }
 @book{geosynthetics in reinforcement and hydraulic applications_2007, ISBN={9780784409091}, url={http://dx.doi.org/10.1061/9780784409091}, DOI={10.1061/9780784409091}, abstractNote={Proceedings of Geo-Denver 2007, New Peaks in Geotechnics, held in Denver, Colorado, February 18-21, 2007. Sponsored by the Geo-Institute of ASCE. This Geotechnical Special Publication contains 17 papers on the use of geosynthetics in earth structures by the construction industry. These papers present aspects related to recent advances in field and laboratory performance of geosynthetics as reinforcement and drainage materials. Topics include the characterization of geotextile voids; the interaction of geosynthetics with the surrounding soils; and construction aspects related to slopes, walls, and embankments on soft soils. Innovative approaches to design for efficient utilization of reinforcement capacity are presented.}, publisher={American Society of Civil Engineers}, year={2007}, month={Oct} }
 @inproceedings{gabr_borden_smith_denton_2007, title={Laboratory Characterization of Jetting-Induced Disturbance Zones}, volume={172}, DOI={10.1061/40916(235)15}, abstractNote={A laboratory study is performed to develop a model for evaluating the extent of the disturbance zone created by the pile jetting process. The physical phenomenon of jetting was observed in three different sands. Observations indicated that installation of piles by jetting is from the simultaneous erosion of sand beneath the pile tip and transport of soil particles through an annulus created around the circumference of the pile up to the ground surface. The pile advances only after a sufficient area has been eroded beneath the tip to cause a bearing capacity failure, as side friction is reduced due to the return water and liquefaction of sand within the annulus. Given equal jetting parameters, the extent of the debris zone from the pile center was approximately 100% further for sand with smaller average particle sizes (D50 = 0.15 mm) than for sand with larger average particle size (D50 = 0.5 mm). An empirical model to provide dimensional characteristics of the disturbance zone is proposed based on data from the laboratory study. Further research into the effect of jetting and water currents on disturbance zone is warranted including monitoring of field installations to verify the proposed model.}, booktitle={Soil Improvement}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A. and Borden, Roy H. and Smith, Alex W. and Denton, Raymond L.}, year={2007}, month={Oct} }
 @inproceedings{park_gabr_borden_kim_kreider_2007, title={Limit Equilibrium and Deformation Analyses of a Geogrid-Reinforced Embankment}, volume={165}, DOI={10.1061/40909(228)17}, abstractNote={Limit equilibrium analyses and 2-dimensional numerical simulations are performed to estimate the performance of a geosynthetic-reinforced embankment supporting a bridge abutment. Geogrid reinforcement was evaluated as a means of improving the stability of the embankment slope and reducing deformation under design loads. Results indicated a reduction in total and differential deformation due to the inclusion of reinforcement. The deformation of the embankment slope was correlated to the global factor of safety. Vertical and lateral movements for the reinforced case were computed to be 65% and 78%, respectively, of those of the unreinforced embankment case. The load carrying capacity of the reinforced embankment was estimated to be 5 times larger than the unreinforced case while providing the same limit equilibrium factor of safety.}, booktitle={Geosynthetics in Reinforcement and Hydraulic Applications}, publisher={American Society of Civil Engineers (ASCE)}, author={Park, Young Jin and Gabr, Mohammed A. and Borden, Roy H. and Kim, Kyung Jun and Kreider, Christopher A.}, year={2007}, month={Oct} }
 @inproceedings{vidot?vega_possiel_robinson_kowalsky_gabr_2007, title={Moment transfer in bearing supported Bridges}, booktitle={2007 PCI-FHWA National Bridge Conference, AZ, October 2007}, author={Vidot?Vega, A. L. and Possiel, B. and Robinson, B. and Kowalsky, M. and Gabr, M. A.}, year={2007} }
 @article{gabr_hossain_barlaz_2007, title={Shear Strength Parameters of Municipal Solid Waste with Leachate Recirculation}, volume={133}, DOI={10.1061/(ASCE)1090-0241(2007)133:4(478)}, abstractNote={The objective of this study was to characterize relative changes in waste shear strength parameters during waste decomposition. Twelve direct shear tests ( 100 mm diameter by 50 mm thickness) were performed on waste specimens ranging from fresh to well-decomposed residential refuse. In addition, nine direct shear tests were performed on selected waste components including fresh paper, partially decomposed refuse, and plastics. Results indicate that the friction angle of refuse decreased with decomposition. As refuse decomposed, the plastic content increased, which contributed to a decrease in friction angle as the friction angle of plastics is 18– 19∘ as compared to 33° for fresh shredded waste. The extent of refuse decomposition was characterized by the cellulose plus hemicellulose to lignin ratio [(C+H)∕L] . The measured friction angle decreased from 32 to 24° as (C+H)∕L decreased from 1.29 to 0.25. The shearing pattern for decomposed refuse showed a peak, followed by residual, which was then followed b...}, number={4}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Hossain, M. S. and Barlaz, M. A.}, year={2007}, month={Apr}, pages={478–484} }
 @inproceedings{gabr_borden_smith_denton_eggleston_broome_2006, title={Characterization of jetting-induced disturbance zones}, booktitle={3rd Annual GEO3 T2 conference & expo 2006, Charlotte, April, 2006}, publisher={Raleigh, NC: NC Department of Transportation}, author={Gabr, M. A. and Borden, R. H. and Smith, A. W. and Denton, R. L. and Eggleston, D. B. and Broome, S. W.}, year={2006} }
 @article{leng_gabr_2006, title={Deformation-Resistance Model for Geogrid-Reinforced Unpaved Road}, volume={1975}, DOI={10.3141/1975-18}, abstractNote={Unpaved road sections experience degradation and accumulation of plastic deformation under repeated loading. Geogrid placed between subgrade and aggregate base course (ABC) can improve section performance through several mechanisms and lead to reduction in stresses and plastic deformation. An unpaved road design model that includes provisions for mobilization of subgrade bearing capacity under axisymmetric condition is proposed. The model incorporates base course property, mobilization of subgrade bearing capacity with rutting, degradation of base course stress attenuation with cyclic load, and the effect of reinforcement inclusion. An elastic layer method has been used to back-analyze the vertical stresses on subgrade with data from previous cyclic plate load tests performed in the laboratory. The degradation of unpaved sections was expressed as a reduction in base course-subgrade elastic modulus ratio (E1/E2) with an increasing number of cycles or a decrease in stress distribution angle of base course. ...}, journal={Transportation Research Record: Journal of the Transportation Research Board}, publisher={Transportation Research Board}, author={Leng, Jianjun and Gabr, Mohammed}, year={2006}, month={Jan}, pages={146–154} }
 @article{warren_gabr_quaranta_2006, title={Field Study to Investigate WIDE Technology for TCE Extraction}, volume={132}, DOI={10.1061/(asce)1090-0241(2006)132:9(1111)}, abstractNote={A full-scale field study was conducted using well injection depth extraction (WIDE) technology to remove trichloroethylene (TCE) from subsurface profiles with fine-grained soils. WIDE incorporates the use of geosynthetic wick drains, attached to an aboveground PVC pipe network, designed to (1) extract contaminated fluids from a specific depth using vacuum pressure, and/or (2) inject flushing solutions. Both extraction-only and concurrent injection-extraction testing schemes were conducted, and fluid flow rates, TCE recovery rates, and groundwater elevations were monitored over a 9 month time interval. During extraction-only operational schemes, gas-phase TCE extraction rates were significantly higher than liquid-phase extraction rates due to the increased volume of air within the geosynthetic wells and PVC piping. TCE extraction rates were less than 2,000 mg∕h for airflow rates less than 100,000 L∕h , and increased significantly to 5,700 mg∕h as the airflow rate approached 600,000 L∕h . Long term testing ...}, number={9}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Warren, K. A. and Gabr, M. A. and Quaranta, J. D.}, year={2006}, month={Sep}, pages={1111–1120} }
 @article{suits_sheahan_harris_shafer_degroff_hater_gabr_barlaz_2006, title={Shear strength of degraded reconstituted municipal solid waste}, volume={29}, DOI={10.1520/gtj14089}, abstractNote={Abstract}, number={2}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Suits, L David and Sheahan, TC and Harris, JM and Shafer, AL and DeGroff, W and Hater, GR and Gabr, M and Barlaz, MA}, year={2006}, pages={141–148} }
 @article{gabr_han_2005, title={Advances in reinforcements for embankments and shallow foundation on soft soils}, volume={141}, journal={ASCE Geotechnical Special Publication}, author={Gabr, M. A. and Han, J.}, year={2005} }
 @inproceedings{gabr_han_2005, title={Geosynthetic Reinforcement for Soft Foundations: US Perspectives}, DOI={10.1061/40788(167)5}, abstractNote={Geosynthetics have been successfully used as reinforcements for embankments and shallow foundation on soft soils. Their applications include the use of geosynthetics for increasing stabilit y of embankments, increasing bearing capacity of footing on soft foundations, creating construction platforms, and bridging over sinkholes. In recent years, geosynthetics mats have also been used in combination with pile or column systems to support embankments over soft foundations. This paper identifies current practices in the above applications including the most prevalent approaches in the US and other countries and presents recent advances reported in literature. Gaps in our current knowledge are identified and possible future directions for research and development are}, booktitle={International Perspectives on Soil Reinforcement Applications}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed and Han, Jie}, year={2005}, month={Oct} }
 @book{zornberg_gabr_bowders_2005, title={International Perspectives on Soil Reinforcement Applications}, number={141}, publisher={ASCE}, year={2005} }
 @article{warren_gabr_2005, title={Liquid extraction through prefabricated vertical well under vacuum in clay}, volume={28}, number={4}, journal={ASTM Geotechnical Testing Journal}, author={Warren, K. and Gabr, M. A.}, year={2005}, pages={328–335} }
 @article{suits_sheahan_warren_gabr_2005, title={Liquid extraction using prefabricated vertical wells (PVWs) under vacuum in clay}, volume={28}, ISSN={["0149-6115"]}, DOI={10.1520/GTJ12113}, abstractNote={Abstract}, number={4}, journal={GEOTECHNICAL TESTING JOURNAL}, publisher={ASTM International}, author={Suits, L David and Sheahan, TC and Warren, KA and Gabr, MA}, year={2005}, month={Jul}, pages={328–335} }
 @article{leng_gabr_2005, title={Numerical analysis of stress-deformation response in reinforced unpaved road sections}, volume={12}, DOI={10.1680/gein.12.2.111.61187}, abstractNote={Aggregate base course (ABC) layers of unpaved structures show significant plastic behavior under traffic load, including stress-dependent modulus and structural degradation. Geosynthetic reinforcement is commonly placed between the ABC and the subgrade to improve the performance of unpaved structures. Numerical analyses using the finite element program ABAQUS were conducted to investigate the performance of geogrid-reinforced aggregate over soft subgrade. Elasto-plastic constitutive models were used to model aggregate, subgrade and geogrid layer. Interaction between geogrid and aggregate was simulated as a shear-resistance interface. The reinforcement effects were seen in reducing surface deformation and improving vertical stress distribution on the subgrade layer. A parametric study indicated that ABC thickness and ABC/ subgrade modulus ratio greatly affect the contribution of the reinforcement. As the ABC thickness decreases, or as the ABC/subgrade modulus ratio decreases owing to deterioration or degradation of the ABC layer, the modeled sections show larger deformation, and the benefit due to geogrid inclusion becomes more apparent. Reinforcement with higher tensile modulus and better interface friction coefficient yielded better section performance in terms of less stress on the subgrade and surface deformation.}, number={2}, journal={Geosynthetics International}, publisher={Thomas Telford Ltd.}, author={Leng, J. and Gabr, M. A.}, year={2005}, month={Mar}, pages={111–119} }
 @article{leng_gabr_2005, title={Numerical analysis of stress–deformation response in reinforced unpaved road sections}, volume={12}, DOI={10.1680/gein.2005.12.2.111}, abstractNote={ Aggregate base course (ABC) layers of unpaved structures show significant plastic behavior under traffic load, including stress-dependent modulus and structural degradation. Geosynthetic reinforcement is commonly placed between the ABC and the subgrade to improve the performance of unpaved structures. Numerical analyses using the finite element program ABAQUS were conducted to investigate the performance of geogrid-reinforced aggregate over soft subgrade. Elasto-plastic constitutive models were used to model aggregate, subgrade and geogrid layer. Interaction between geogrid and aggregate was simulated as a shear-resistance interface. The reinforcement effects were seen in reducing surface deformation and improving vertical stress distribution on the subgrade layer. A parametric study indicated that ABC thickness and ABC/ subgrade modulus ratio greatly affect the contribution of the reinforcement. As the ABC thickness decreases, or as the ABC/subgrade modulus ratio decreases owing to deterioration or degradation of the ABC layer, the modeled sections show larger deformation, and the benefit due to geogrid inclusion becomes more apparent. Reinforcement with higher tensile modulus and better interface friction coefficient yielded better section performance in terms of less stress on the subgrade and surface deformation. }, number={2}, journal={Geosynthetics International}, publisher={Thomas Telford Ltd.}, author={Leng, J. and Gabr, M. A.}, year={2005}, month={Mar}, pages={111–119} }
 @inproceedings{hossain_gabr_2005, title={Prediction of Municipal Solid Waste Landfill Settlement with Leachate Recirculation}, volume={142}, DOI={10.1061/40789(168)50}, abstractNote={The degradation of Municipal Solid Waste (MSW) over time, and associated settlement, is of special importance when estimating air space, designing interim and final closure covers of landfills, as well as planning vertical expansion of existing facilities. Most settlement models applied to solid waste were developed for inorganic soils or peat. Furthermore, these models were not developed considering the leachate recirculation effect on settlement. In case of bioreactor landfills, waste settlement will include creep as well as biological components due to the accelerated degradability of waste particles as leachate is recycled. The objective of this paper is to present a settlement prediction model, which accounts for changes in material characteristics as a function of the waste degradation rate. As biodegradation takes place, the organic solid mass is converted to gas and the void ratio increases with a subsequent increase in waste settlement. In general, published settlement models do not capture these phenomena. The model developed herein is based on the results of an experimental program. Settlement components including creep and biodegradation effects are identified as a function of the state of decomposition. Twenty four one-dimensional oedometer tests (63.5 mm cell) were performed on shredded refuse in laboratory-scale reactors for measurement of compression indices representing primary (Cc), creep (Cαi) and biological (Cβi) on samples ranging from fresh to well-decomposed refuse. Particles of length equal to no more than half the diameter of the test cell were included. The time factors, ti, t2, t3 and t4 for the compressibility were determined from the gas production curve and existing field settlement data, and utilized for model development. The proposed model was verified using the settlement model parameters obtained from laboratory test and comparing predicted settlement with observed field settlement from several landfills.}, booktitle={Waste Containment and Remediation}, publisher={American Society of Civil Engineers (ASCE)}, author={Hossain, M. S. and Gabr, M. A.}, year={2005}, month={Oct}, pages={3837–3850} }
 @inproceedings{bowders_gabr_collazos_quaranta_2005, title={Prefabricated vertical wells for enhanced in situ remediation}, DOI={10.1061/40782(161)34}, abstractNote={Prefabricated vertical drains (PVDs), also known as wick or strip drains, commonly used to accelerate consolidation of fine-grained soils and sludges, have been successfully demonstrated for enhancing in situ remediation of contaminated soils and groundwater. Over the last decade, the technology basis was developed for using PVDs to accelerate in situ flushing, i.e., removal of contaminants below the groundwater table. During the last five years, the basis for using PVDs to enhance soil vapor extraction systems, i.e., removal of contaminated soil gas in the vadose zone was developed. Both of these geosynthetic applications have been field-demonstrated on a limited basis. The first at an abandoned TCE evaporation pond at a U.S. Department of Energy processing plant and the second at a municipal solid waste landfill experiencing subsurface lateral migration of methane gas. The PVD-enhanced remediation technologies have yet to find wide acceptance and utilization. Perhaps if several remaining issues are resolved and additional, well-instrumented field demonstrations are performed with results implemented in a design manual, consultants, remediation contractors and regulatory agencies will begin to include and utilize these technologies among their remediation options. In this paper we present an overview of the PVD-remediations technologies, a brief description of some past field demonstrations and our thoughts on research/development issues necessary to further the use of this technology.}, booktitle={Geosynthetics Research and Development in Progress (GRI-18) : Geo-Frontiers 2005}, publisher={Reston, Va. : American Society of Civil Engineers}, author={Bowders, J. J. and Gabr, M. A. and Collazos, O. M. and Quaranta, J. D.}, year={2005} }
 @article{kim_rahman_gabr_sarica_hossain_2005, title={Reliability based calibration of resistance factors for axial capacity of driven piles}, volume={132}, ISBN={9780784407783}, url={http://dx.doi.org/10.1061/40778(157)12}, DOI={10.1061/40778(157)12}, abstractNote={Resistance factors were calibrated using the framework of reliability theory for the Load and Resistance Factor Design (LRFD) of driven pile’s axial capacity in North Carolina utilizing pile load test data available from the North Carolina Department of Transportation (NCDOT). A total of 140 Pile Driving Analyzer (PDA) data and 35 static load test data were compiled and grouped into different design categories based on four pile types and two geologic regions. Resistance statistics were evaluated for each design category in terms of bias factors. Reliability analysis of the current NCDOT practice of pile foundation design was performed to evaluate the level o f safety and to select the target reliability indices. Resistance factor calibration was performed for the three methods of static pile capacity analysis commonly used in the NCDOT: the Vesic (1977), the Nordlund (1963), and the Meyerhof (1976) methods. Two types of First Order Reliability Methods (Mean Value First Order Second Moment method and Advanced First Order Second Moment method) were used for the reliability analysis and the calibration of the resistance factors. The calibrated resistance factor s varied significantly for the different pile types and geologic regions. The advanced first order second moment method resulted in larger resistance factors than the mean value first order second moment method. Recommended resistance factors are presented for the three methods of static pile capacity analysis and for seven different design categories of pile types and geologic regions.}, journal={ASCE Geotechnical Special Publication}, publisher={American Society of Civil Engineers}, author={Kim, K. J. and Rahman, M. S. and Gabr, M. A. and Sarica, R. Z. and Hossain, M. S.}, year={2005}, pages={735–746} }
 @book{slopes and retaining structures under seismic and static conditions_2005, ISBN={9780784407875}, url={http://dx.doi.org/10.1061/9780784407875}, DOI={10.1061/9780784407875}, abstractNote={Proceedings of Geo-Frontiers 2005, held in Austin, Texas, January 24-26, 2005. Sponsored by the Geo-Institute of ASCE. This Geotechnical Special Publication contains 32 papers on the design of slopes and retaining structures that continue to pose challenges to geotechnical engineers. These include long-term performance under static and seismic conditions and in harsh environments, issues related to use of nontraditional backfills, and the reliability of the constructed systems throughout the design life. Several challenges related to design and construction of slopes and retaining structures are addressed with the increased utilization of geosynthetics. The level of activities associated with geosynthetics reinforcement range from paved and unpaved roads to the construction of segmental retaining walls and slopes. Field and laboratory performance of retaining walls and slopes under seismic and static conditions are presented. National and international experts discuss performance of reinforced and unreinforced pavement systems, slopes and retaining structures in harsh environments and under severe conditions.}, publisher={American Society of Civil Engineers}, year={2005}, month={Oct} }
 @inproceedings{kunberger_gabr_2005, title={Temperature Effect on Desorption Kinetics of Benzene on Various Soils}, volume={142}, DOI={10.1061/40789(168)35}, abstractNote={Since the advent of diesel fuel use, insufficient storage and inadequate transport and disposal practices have resulted in widespread contamination of the subsurface environment. Beginning in the 1970's, the United States EPA has established a number of regulations controlling current and future storage, transport, and disposal efforts and address the need to remediate existing contaminated sites. However, regulations provide only the desired goal, not a roadmap of how to accomplish remediation. It falls then, to individuals in research and industry, to devise techniques effective in reducing / eliminating contamination levels at sites of concern. Existing remediation techniques of pump and treat and air sparing / soil vapor extraction are effective, but often take many years to accomplish remediation to regulatory levels. Thermal treatments such as steam stripping and electrical heating of soils, are much less time consuming, but much more costly endeavors. Low temperature thermal desorption (at temperatures less than 80 degrees C) holds promise by incorporating the benefits of higher temperatures, such as the increase in vapor pressure and the decrease in viscosity, without the extreme cost usually associated with thermal treatments. In order to test this hypothesis, a research testing program focused on batch testing in the laboratory setting was developed to assess the viability of increased temperatures on the desorption efficiency of benzene on various soils. Testing consisted of three soils, a poorly graded Ottowa sand, kaolinite, and a natural silty sand soil from the Lockbourne Air Force Base experimental testing site. The contaminant of concern is benzene, a carcinogenic and mutagenic compound that is one of the four major components of BTEX, a constituent of most diesel fuels. Benzene was chosen because of its presence at the LAFB testing site at contamination levels 164 times groundwater regulation limit of 5 ppb. Laboratory testing was conducted at initial benzene solution concentrations of 10, 100 and 1000 mg/L. Four temperatures; 20, 40, 60, and 80 degrees C, were used in the batch testing program. Results from testing support the theory that increased temperatures result in higher desorption efficiency. For lower concentrations of 10 and 100 ppm, temperatures as low as 40 degrees C correlated to increases in desorption levels from 40 percent (at 20 degrees C) to over 80 percent for the kaolinite and natural soil. Sand also experienced a doubling in desorption efficiency (from roughly 30 percent to roughly 70 percent) at the 60 degrees C temperature and 10 and 100 ppm concentrations. The 1000 ppm testing concentration resulted in more modest, but still increasing removal efficiencies at increased temperatures. Remediation at moderately increased temperatures appears to be a promising technique, but further research needs to be performed on soils that have experienced long term exposure to contamination to assess whether or not increased desorption efficiency trends are maintained.}, booktitle={Waste Containment and Remediation}, publisher={American Society of Civil Engineers (ASCE)}, author={Kunberger, T. and Gabr, M. A.}, year={2005}, month={Oct}, pages={3649–3659} }
 @inproceedings{quaranta_kunberger_gabr_2005, title={WIDE Application for Subsurface Hydraulic Head Control}, volume={142}, DOI={10.1061/40789(168)41}, abstractNote={This paper addresses field testing and numerical modeling that investigated use of the Well Injection Depth Extraction (WIDE) technology for saturating a subsurface profile. Although not detailed in this paper, the purpose of delivering liquid to the unsaturated subsurface zone was to extract radioactive contaminants (primarily cesium) at the U.S. Department of Energy Columbus Closure Site's West Jefferson North (WJN) facility (JN-1 Abandoned Filter Bed). The objective of the field testing was to investigate injection flow rate distribution through the piping header and manifold assembly to the soil, investigate the rise in subsurface water table corresponding to pulse and gradual injection modes, and establish water table mounding with time. Results show that a pulse injection caused a localized rise in the subsurface water elevation with subsequent decline over 2–3 hours. A gradual injection leads to a more uniform rise in piezometric head albeit at a smaller magnitude. In one specific test, 4,164 liters of injected water resulted in a mound that extended approximately 10 m down gradient of the test pad area and 5 m up gradient. The maximum mounding front occurred approximately 2 to 3 hrs after completion of the injection cycle. Approximately 0.3 to 0.6 m of rise in subsurface water elevation was recorded with the gradual injection model. In this case, the impacted zone was contained within the area of injection (4.5 m x 4.5 m). Pulse injection from pumped delivery was determined to be more effective than gradual injection in rising and maintaining subsurface water elevations to levels necessary for saturation of soil containing the maximum cesium contamination. Modeling results using Seep/W Version 5 from Geo-Slope International compared well with field measurements.}, booktitle={Waste Containment and Remediation}, publisher={American Society of Civil Engineers (ASCE)}, author={Quaranta, J. D. and Kunberger, T. and Gabr, M. A.}, year={2005}, month={Oct}, pages={3725–3736} }
 @inproceedings{gupta_gabr_matzen_2004, title={Alternatives in the implementation of internet-enabled laboratory experiments in undergraduate civil engineering courses}, booktitle={ASEE 2004 annual conference & exposition$h[electronic resource] :June 20-23, 2004, Salt Lake City, Utah : Engineering education reaches new heights : conference proceedings}, publisher={Washington, D.C.: American Soceity for Engineering Education}, author={Gupta, A. and Gabr, M. A. and Matzen, V. C.}, year={2004} }
 @inproceedings{warren_gabr_2003, title={A well injection depth extraction (WIDE) field demonstration}, ISBN={9783773959850}, booktitle={Soil and Rock America 2003 :12th Panamerican Conference on Soil Mechanics and Geotechnical Engineering}, publisher={Essen: Verlag Glu?ckauf GMBH}, author={Warren, K. and Gabr, M. A.}, editor={P. J. Culligan, H. H. Einstein and Whittle, A. J.Editors}, year={2003} }
 @inproceedings{hossain_gabr_barlaz_2003, title={Effect of decomposition and stress on creep compression index of municipal solid waste in bioreactor landfills}, ISBN={9783773959850}, booktitle={Soil and Rock America 2003 :12th Panamerican Conference on Soil Mechanics and Geotechnical Engineering}, publisher={Essen: Verlag Glu?ckauf GMBH}, author={Hossain, M. S. and Gabr, M. A. and Barlaz, M.}, editor={P. J. Culligan, H. H. Einstein and Whittle, A. J.Editors}, year={2003} }
 @inproceedings{kunberger_quaranta_gabr_2003, title={Extraction of JP-4 using well injection depth extraction (WIDE): Field demonstration}, ISBN={9783773959850}, booktitle={Soil and Rock America 2003 :12th Panamerican Conference on Soil Mechanics and Geotechnical Engineering}, publisher={Essen: Verlag Glu?ckauf GMBH}, author={Kunberger, T. and Quaranta, J. D. and Gabr, M. A.}, editor={P. J. Culligan, H. H. Einstein and Whittle, A. J.Editors}, year={2003} }
 @article{hossain_gabr_barlaz_2003, title={Relationship of Compressibility Parameters to Municipal Solid Waste Decomposition}, volume={129}, DOI={10.1061/(ASCE)1090-0241(2003)129:12(1151)}, abstractNote={Recently, there has been substantial interest in the enhancement of refuse decomposition in landfills, which results in increased settlement. In this paper, changes in waste compressibility as a function of the state of decomposition are reported. Samples representative of residential refuse were decomposed under conditions designed to simulate decomposition in both control and bioreactor landfills. Twenty four one-dimensional oedometer tests (63.5 mm cell) were performed on refuse prepared in laboratory-scale reactors for measurement of primary (Cc) and secondary (Ci, representing creep, and Ci, representing biological) compression indices. The state of decomposition was quantified by the methane yield and the cellulose (C) plus hemicellulose (H) to lignin (L) ratio. The magnitude of compressibility was shown to increase as refuse decomposed and compressibility parameters were correlated with the state of decomposition. Initial settlement increased with decreasing (C + H)/L ratio while the creep index was fairly independent of the state of decomposition. The coefficients of primary compression (Cc) for bioreactor samples showed an increasing trend with decreasing (C + H)/L ratios. Cc increased from 0.16 to 0.36 as (C + H)/L decreased from 1.29 to 0.25, and similar values of Cc were obtained with control samples at similar (C + H)/L ratios. The creep index range was estimated at 0.020.03 for control and bioreactor samples in various states of decomposition. The magnitude of the biological degradation index (Ci) depended on the degradation phase with the highest value of 0.19 obtained during the phase of accelerated methane production. Proposing a single Cc for landfill settlement calculations may lead to inaccurate predictions. Properties of each waste sublayer will change as a function of the decomposition stage, and dominating processes with appropriate compressibility parameters should be applied to individual sublayers.}, number={12}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Hossain, M. S. and Gabr, M. A. and Barlaz, M. A.}, year={2003}, pages={1151–1158} }
 @inbook{leng_gabr_2002, title={Characteristics of geogrid-reinforced aggregate under cyclic load}, volume={1786}, ISBN={0309077117}, DOI={10.3141/1786-04}, abstractNote={ The characteristics of geogrid-reinforced aggregates over soft subgrade soil were investigated through a laboratory-testing program. Nine cyclic plate load tests were conducted with varying base layer thickness and reinforcement type. Results indicated that aggregate base course (ABC) degraded under cyclic loading as manifested by an increase in stresses at the interface between the ABC and the subgrade with increasing number of cycles. The improvement in stress distribution due to geosynthetic inclusion at the interface of ABC and subgrade soil is indicated by a decrease in the measured maximum stress (under the center of the loaded area) and the measurement of a more uniform stress distribution on the subgrade soil layer. The higher modulus geogrid provided a better load-spreading effect compared with a lower modulus geogrid used in the testing. The improvement in plastic surface deformation was related to two aspects: ( a) decrease in vertical deformation of the subgrade and ( b) decrease in lateral spread of the ABC. A model that incorporates the mechanics of reinforcement contributions to deformation and stresses and the effect of ABC degradation as a function of number of load cycles needs to be developed for the transportation community to fully realize the benefits of reinforcement in such an application. }, number={1}, booktitle={Geology and properties of earth materials, 2002}, publisher={Washington, DC: National Academy Press}, author={Leng, J. J. and Gabr, M. A.}, year={2002}, pages={29–35} }
 @article{barlaz_rooker_kjeldsen_gabr_borden_2002, title={Critical evaluation of factors required to terminate the postclosure monitoring period at solid waste landfills}, volume={36}, ISSN={["1520-5851"]}, DOI={10.1021/es011245u}, abstractNote={Regulations governing the disposal of solid waste in landfills specify that they must be monitored for 30 years after closure unless this period is extended by the governing regulatory authority. Given the wide range of conditions under which refuse is buried, technical criteria, rather than a specific time period, are preferable for evaluation of when it is acceptable to terminate postclosure monitoring. The objectives of this paper are to identify and evaluate parameters that can be used to define the end of the postclosure monitoring period and to present a conceptual framework for an investigation of whether postclosure monitoring can be terminated at a landfill. Parameters evaluated include leachate composition and leachate and gas production. Estimates of leachate production from closed landfills are used to assess the potential environmental impacts of a hypothetical release to surface water or groundwater. The acceptability of gaseous releases should be evaluated against criteria for odors, the potential for subsurface migration, and greenhouse gas and ozone precursor emissions. The approach presented here must be tested on a site-specific basis to identify additional data requirements and regulatory activity that might be required to prepare regulators for the large number of requests to terminate postclosure monitoring expected over the next 20 years. An approach in which the frequency and extent of postclosure monitoring is reduced as warranted by site-specific data and impact analysis should provide an effective strategy to manage closed landfills.}, number={16}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Barlaz, MA and Rooker, AP and Kjeldsen, P and Gabr, MA and Borden, RC}, year={2002}, month={Aug}, pages={3457–3464} }
 @inproceedings{akram_gabr_2002, title={Effect of flow-modifiers on permeation behavior of fly ash with a nonwoven geotextile}, booktitle={37th Engineering Geology and Geotechnical Engineering Symposium, Soil Properties, Boise, Idaho, March 2002}, publisher={Pocatello, Idaho : College of Engineering, Idaho State University}, author={Akram, M. A. and Gabr, M. A.}, year={2002} }
 @article{han_gabr_2002, title={Numerical Analysis of Geosynthetic-Reinforced and Pile-Supported Earth Platforms over Soft Soil}, volume={128}, DOI={10.1061/(ASCE)1090-0241(2002)128:1(44)}, abstractNote={Geotechnical engineers face several challenges when designing structures over soft soils. These include potential bearing failure, intolerable settlement, large lateral pressures and movement, and global or local instability. Geosynthetic-reinforced and pile- supported earth platforms provide an economic and effective solution for embankments, retaining walls, and storage tanks, etc. con- structed on soft soils; especially when rapid construction and/or strict deformation of the structure are required. The inclusion of geosynthetic~s! in the fill enhances the efficiency of load transfer, minimizes yielding of the soil above the pile head, and potentially reduces total and differential settlements. A numerical study has been conducted to investigate pile-soil-geosynthetic ~s! interactions by considering three major influence factors: the height of the fill, the tensile stiffness of geosynthetic, and the elastic modulus of pile material. While current methods have not fully addressed important effects of the geosynthetic stiffness and pile modulus on the soil arching ratio, numerical results suggested that the stress concentration ratio and the maximum tension in geosynthetic increase with the height of the embankment fill, the tensile stiffness of geosynthetic, and the elastic modulus of the pile material. The distribution of tension force in the geosynthetic reinforcement indicated that the maximum tension occurs near the edge of the pile.}, number={1}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Han, J. and Gabr, M. A.}, year={2002}, month={Jan}, pages={44–53} }
 @article{chaney_demars_gabr_coonse_lambe_2001, title={A Potential Model for Compaction Evaluation of Piedmont Soils Using Dynamic Cone Penetrometer (DCP)}, volume={24}, DOI={10.1520/gtj11349j}, abstractNote={Abstract}, number={3}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Chaney, RC and Demars, KR and Gabr, MA and Coonse, J and Lambe, PC}, year={2001}, pages={308} }
 @inproceedings{ellithy_gabr_2001, title={A model for interface shear strength of nonwoven geotextile}, ISBN={9780935803006}, booktitle={Geosynthetics Conference 2001 :economics, performance and constructibility advantages of geosynthetics, February 12-14, 2001, Portland, Oregon, USA : conference proceedings}, publisher={Roseville, MN : Industrial Fabrics Association International}, author={Ellithy, G. S. and Gabr, M. A.}, year={2001} }
 @inproceedings{quaranta_gabr_sabodish_gates_2001, title={A well injection depth extraction (WIDE) soil flushing for DNAPL and uranium remediation}, booktitle={Waste Management 2001, Tucson, AZ, April 2001}, author={Quaranta, J. and Gabr, M. A. and Sabodish, M. and Gates, K.}, year={2001} }
 @article{gates_aragona_sabodish_gabr_2001, title={Adsorption and Desorption Capacity of Trichloroethylene on Glacial Till with High-Percent Fines}, volume={1755}, ISBN={0309072166}, DOI={10.3141/1755-15}, abstractNote={ An investigation of trichloroethylene (TCE) mobility in glacial till, as manifested by adsorption and desorption behavior with water, surfactant, and sodium chloride, was conducted. In conjunction with natural attenuation, adsorption and desorption kinetics of surfactant are of interest if other remediation technologies, such as pump and treat, are used. A soil solution ratio of 2:1 with equilibrium times of 48 and 40 h for adsorption and desorption, respectively, was found to produce representative kinetics. The adsorption and desorption partition coefficients for TCE in water are 1.25 mL/g and 11.25 mL/g, respectively. The difference in these values is attributed to the heterogeneous nature of the test soil and hindered diffusion through the intraparticles of the soil and organic matter. Sorption of TCE to glacial till is reduced during adsorption and desorption testing with the use of a surfactant due to a decrease in interfacial tension and an increase in micellar solubilization. However, the effects of surfactant concentrations greater than 4 percent are minimal. The sodium chloride concentration is also varied during testing. As salinity increases, the adsorption and desorption coefficients increase and the solubility potential decreases for the same surfactant concentration. These results are attributed to Winsor Type phase changes that were observed independently of adsorption and desorption testing by varying the amounts of surfactant and sodium chloride with TCE. The methods used and results obtained from the testing program are described, and the mobility of the TCE within the test soil in view of the test parameters is discussed. }, number={1755}, journal={Transportation Research Record: Journal of the Transportation Research Board}, publisher={Transportation Research Board}, author={Gates, Kimberly and Aragona, Keith and Sabodish, Michael and Gabr, M.}, year={2001}, month={Jan}, pages={141–148} }
 @inproceedings{barlaz_gabr_hossain_rooker_kjeldsen_2001, title={Closing gaps in the regulation of MSW landfills: Defining the end of the post-closure monitoring period and the future stability of leachate recirculation landfills}, booktitle={Waste Tech 2001 :  February 11 - 14, 2001, Hyatt Islandia, San Diego, CA}, author={Barlaz, M. A. and Gabr, M. A. and Hossain, S. and Rooker, A. and Kjeldsen, P.}, year={2001} }
 @article{gabr_coonse_lambe_2001, title={Compaction control of piedmont soils using dynamic cone penetrometer}, volume={24}, number={3}, journal={ASTM Geotechnical Testing Journal}, author={Gabr, M. A. and Coonse, J. and Lambe, P. C.}, year={2001}, pages={308–313} }
 @article{cho_clark_keaney_gabr_borden_2001, title={Laterally Loaded Drilled Shafts Embedded in Soft Rock}, volume={1772}, ISBN={0309072360}, DOI={10.3141/1772-01}, abstractNote={ The current design criterion for laterally loaded drilled shafts embedded in weathered Piedmont rock profiles requires a challenging effort on the part of the engineer. A substantial cost saving could be realized, while maintaining an acceptable and safe performance, if a rational method were developed for the analysis and design of drilled shafts in such a profile. In a current research project, the primary objective is to develop and validate a procedure for design and analysis of laterally loaded drilled shafts embedded in the Piedmont weathered rock profiles. A major component of this research is a field-testing program. Presented are the results of the first in a series of several lateral load tests performed on two drilled shafts 0.762 m (30 in.) in diameter embedded in Piedmont weathered rock. These shafts were instrumented with inclinometers and strain gauges. Field data obtained from the instrumented shafts were used to develop P-y curves. Field testing also encompassed the use of a borehole dilatometer to establish correlations between the rock strength and deformation parameters and potential P-y curves. A comparison is made between backcalculated P-y curves, P-y curves predicted by using Reese’s method, and P-y curves from the rock dilatometer. Loaddeformation results are presented and discussed for all methods used. }, number={1772}, journal={Transportation Research Record: Journal of the Transportation Research Board}, publisher={Transportation Research Board}, author={Cho, Kook and Clark, Shane and Keaney, Brian and Gabr, Mohammed and Borden, Roy}, year={2001}, month={Jan}, pages={3–11} }
 @inproceedings{akram_gabr_2001, title={Long-term filtration of nonwoven geotextile with fly ash: Post-testing evaluation}, booktitle={36th Engineering Geology and Geotechnical Engineering Symposium, Las Vegas, Nevada March 2001}, author={Akram, M. H. and Gabr, M. A.}, year={2001}, pages={130–1402} }
 @inproceedings{sabodish_gabr_2001, title={Stability of clay suspensions in the presence of surfactant, electrolyte, and DNAPL}, ISBN={9789026518539}, booktitle={Proceedings of the Fifteenth International Conference on Soil Mechanics and Geotechnical Engineering :Istanbul, 27-31 August 2001}, publisher={Exton, PA : Balkema}, author={Sabodish, M. and Gabr, M. A.}, year={2001} }
 @inproceedings{ellithy_gabr_2000, title={Compaction Moisture Effect on Geomembrane/Clay Interface Shear Strength}, volume={103}, DOI={10.1061/40515(291)2}, abstractNote={Results of 72 unconsolidated undrained (UU) and consolidated undrained (CU) direct shear tests on kaolin clay interfaces with two geosynthetic materials are presented. Tests are conducted using smooth High Density Polyethylene (HDPE) and textured HDPE geomembranes. Each interface is tested under four normal stresses: 25, 100, 250, and 500 kPa. The effects of compaction moisture content and pre-shear compression/consolidation conditions on the interface properties are investigated. A discussion on fundamental aspects related to interface shear strength and efficiency is presented. Results indicated that an increase in the clay compaction moisture content leads to a decrease in the shear strength of the sheared as-compacted interfaces. The overall efficiency of the clay/textured HDPE interface is approximately 1 when tested under UU condition, indicating that failure plane is passing through the clay particles. Under CU condition, the pre-shearing compression/consolidation process allowed interlocking between the clay particles and the geomembrane's texturing. Such interlocking yielded an interface efficiency higher than 1 (interface efficiency is defined as the ratio of the interface shear strength to the clay shear strength at the same testing conditions). In CU tests, and for saturated and wet of optimum compacted kaolin/textured HDPE, an increase in the shear strength of the interface and in the overall efficiency is estimated due to an increase in the length of the failure path along which shearing takes place.}, booktitle={Advances in Transportation and Geoenvironmental Systems Using Geosynthetics}, publisher={American Society of Civil Engineers (ASCE)}, author={Ellithy, G. S. and Gabr, M. A.}, year={2000}, month={Jul}, pages={39–53} }
 @article{gabr_bowders_2000, title={Controlled low-strength material using fly ash and AMD sludge}, volume={76}, ISSN={["0304-3894"]}, DOI={10.1016/S0304-3894(00)00202-8}, abstractNote={Controlled low-strength material (CLSM) is a cementitious material with properties similar to stabilized soil. After hardening, CLSM provides adequate strength in bearing capacity and support but can also be easily excavated. To be classified as a CLSM, the material must have a compressive strength between 450 kPa (65 psi) and 8400 kPa (1200 psi). Typical CLSM contains coal-combustion fly ash (FA), cement, water and fine or coarse aggregate. In this paper, physical and strength properties of CLSM formed by combining sludge, a by-product from the treatment of acid mine drainage (AMD), with Class F FA are investigated. The sludge is a lime-based waste product that when combined with FA, exhibits self-hardening characteristics similar to cement. A main focus of this research is to develop a CLSM mix in which by-product material utilization is maximized while satisfying workability and performance requirements. A mixture of 10% AMD sludge, 2.5% Portland cement (PC), 87.5% Class F FA (dry wt.%) with water provided unconfined compressive strength values within the range for classification as CLSM. This mixture satisfies the excavatability and walkability requirements as well as the hardening time and stability criteria.}, number={2-3}, journal={JOURNAL OF HAZARDOUS MATERIALS}, publisher={Elsevier BV}, author={Gabr, MA and Bowders, JJ}, year={2000}, month={Sep}, pages={251–263} }
 @article{gabr_hopkins_coonse_hearne_2000, title={DCP Criteria for Performance Evaluation of Pavement Layers}, volume={14}, DOI={10.1061/(asce)0887-3828(2000)14:4(141)}, abstractNote={The potential use of the dynamic cone penetrometer (DCP) for evaluation of the pavement distress state is investigated. A model to predict the distress level of pavement layers using penetration rate (PR) values of the subgrade and aggregate base course (ABC) layers is proposed based on the coupled contribution of the subgrade and the ABC materials. The developed distress model is validated using field data from four test sites. The two sites with good condition rating values (equal to 4 and 3) are found to have an unconfined PR-ABC value 4 mm/blow) is explained by the fact that field-measured California bearing ratio values for the ABC layer are affected by the strength of the underlying subgrade soils. This is especially observed in cases where the thickness of the ABC layer is <102 mm (4 in.). The framework of the established procedure can generally be used at other sites, properly taking into account differences in material properties.}, number={4}, journal={Journal of Performance of Constructed Facilities}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Hopkins, Kelly and Coonse, Jeffery and Hearne, Tom}, year={2000}, month={Nov}, pages={141–148} }
 @inbook{gabr_2000, place={New York}, title={Design Considerations of Hazardous Waste Landfills}, booktitle={Remediation Engineering of Contaminated Soils}, publisher={Marcel Dekker Inc.,}, author={Gabr, M.}, editor={Wise, D.L. and Trantolo, D.J.Editors}, year={2000}, month={Jul}, pages={83–93} }
 @article{gabr_hopkins_coonse_hearne_2000, title={Dynamic cone penetrometer criteria for evaluation of aggregate base courses}, volume={14}, number={4}, journal={Journal of Performance of Constructed Facilities}, author={Gabr, M.A. and Hopkins, K. and Coonse, J. and Hearne, T.}, year={2000}, pages={324–349} }
 @article{chaney_demars_gabr_hart_2000, title={Elastic modulus of geogrid-reinforced sand using plate load tests}, volume={23}, DOI={10.1520/gtj11049j}, abstractNote={Abstract}, number={2}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Chaney, RC and Demars, KR and Gabr, MA and Hart, JH}, year={2000}, pages={245–250} }
 @inproceedings{quaranta_sabodish_gates_gabr_2000, title={Enhanced Subsurface Flushing of Mixed Waste: A Field Study}, volume={105}, DOI={10.1061/40519(293)10}, abstractNote={Contamination in low permeability, high clay fraction soil poses a significant technical challenge to in situ remediation efforts. Traditional technologies such as pump-and-treat groundwater remediation and vapor extraction using well fields have been rather ineffective when applied to sites with low permeability soils. The extraction of the contaminant from the soil and movement of the flushing solution are restricted due to the pore size, soil fabric arrangement, and adsorption characteristics of the fine-grain soils. An innovative subsurface remediation technology termed Well Injection Depth Extraction (WIDE) has been developed and demonstrated by North Carolina State University (NCSU). The WIDE system is a hybrid subsurface flushing/vapor-gas extraction system that uses Prefabricated Vertical Wells (PVWs) for the in situ remediation of contaminated groundwater and fine-grained soils with hydraulic conductivities ranging from 10–3 to 10–8 cm/s. The WIDE system has been demonstrated in the field for removal of groundwater having soluble contaminant waste streams, dense non-aqueous phase liquids (DNAPLs), and light non-aqueous phase liquids (LNAPLs). The field demonstration case study is described in this paper.}, booktitle={Environmental Geotechnics}, publisher={American Society of Civil Engineers (ASCE)}, author={Quaranta, J. D. and Sabodish, M. S. and Gates, K. A. and Gabr, M. A.}, year={2000}, month={Jul}, pages={132–141} }
 @article{quaranta_gabr_2000, title={Prefabricated Vertical Drains Flow Resistance under Vacuum Conditions}, volume={126}, DOI={10.1061/(ASCE)1090-0241(2000)126:1(81)}, abstractNote={The results of experimental research are presented and discussed with focus on the internal well resistance of prefabricated vertical drains (PVDs) under vacuum-induced water flow. Measured results included fluid flow rates for two different cross-sectional hydraulic profiles (Types I and II PVDs). Experimental results indicated linear relationships, independent of the PVD widths, between extracted fluid velocity and the applied hydraulic gradient. Data showed a laminar flow regime to predominate for test velocities corresponding to hydraulic gradients less than 0.5. The larger nominal hydraulic radius of the Type II PVD is credited with providing a flow rate equal to approximately 3.2 times that of the Type I PVD at approximately the same operating total head. No apparent dependency of the transmissivity (theta) was found on the width or lengths (3 m, 4 m, and 5 m) of the PVDs tested. In the case of the 100-mm-wide Type I PVD, theta = 618 sq mm/s was estimated from the measured data versus theta = 1,996 sq mm/s for Type II PVD with the same dimensions.}, number={1}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Quaranta, J. D. and Gabr, M. A.}, year={2000}, month={Jan}, pages={81–84} }
 @article{gabr_bowders_2000, title={Properties of controlled low strength material (CLSM) consisting of fly ash and AMD sludge}, volume={76}, number={2-3}, journal={Journal of Hazardous Materials}, author={Gabr, M. A. and Bowders, J. J.}, year={2000}, pages={251–263} }
 @article{gabr_hossain_barlaz_2000, title={Waste settlement in bioreactor landfills}, volume={18}, number={2}, journal={Geotechnical News}, author={Gabr, M. A. and Hossain, M. S. and Barlaz, M. A.}, year={2000}, pages={50–55} }
 @article{gabr_sabodish_williamson_bowders_1999, title={BTEX Extraction from Clay Soil Using Prefabricated Vertical Drains}, volume={125}, DOI={10.1061/(ASCE)1090-0241(1999)125:7(615)}, abstractNote={A pilot scale field test was conducted to demonstrate the feasibility of using prefabricated vertical drains (PVDs) for in-situ point extraction of benzene, toluene, ethylbenzene, and xylene (BTEX) under vacuum. Results indicated the achievement of an average flow rate of 16.7 mL/s for the five PVD systems. Grab samples from the effluent indicated an increase in retrieved BTEX concentration with time. Maximum retrieved concentrations in a 2-day period were ∼0.4 mg/L for benzene, 0.27 mg/L for toluene, 0.19 mg/L for ethylbenzene, and 0.025 mg/L for xylene. Based on the limited results of the pilot scale test, a full-scale remediation of the site using the PVDs system is deemed feasible.}, number={7}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Sabodish, Mike and Williamson, Alan and Bowders, John J.}, year={1999}, month={Jul}, pages={615–618} }
 @article{gabr_1999, title={Characteristics of urethane-grouted sand for in situ seepage control}, volume={90}, journal={ASCE Geotechnical Special Publication}, author={Gabr, M. A.}, year={1999} }
 @article{chen_gabr_1999, title={Discussion of “Representation of Compacted Clay Minifabric Using Random Networks” by J. Chen and M. A. Gabr}, volume={125}, DOI={10.1061/(asce)1090-0241(1999)125:4(336)}, number={4}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Chen, J. and Gabr, M. A.}, year={1999}, month={Apr}, pages={336–337} }
 @inproceedings{gabr_sabodish_1999, title={Flushing of ethylbenzene?contaminated clay using Tergitol}, ISBN={9780784404355}, booktitle={Environmental engineering, 1999 :proceedings of ASCE-CSCE National Conference on Environmental Engineering : July 25-28, 1999, Norfolk, Virginia}, publisher={Reston, Va. : American Society of Civil Engineers}, author={Gabr, M. A. and Sabodish, M.}, year={1999} }
 @article{atuahene_chen_gabr_reddi_thangavadivelu_1999, title={Representation of Compacted Clay Minifabric Using Random Networks}, volume={125}, DOI={10.1061/(asce)1090-0241(1999)125:4(335.2)}, abstractNote={Two discussions of a paper with the aforementioned title by L.N. Reddi and S. Thangavadivelu, published in this journal (Volume 122, Number 11, November 1996), are presented. The first discusser questions the validity of Equation (11) in the authors' paper, which calculates cluster radii with the inversion method, pointing out that the cluster diameters generated by the inversion method and the quadratic formula are substantially different from the pore diameters, which are the experimental cluster diameters. Discussers Chen and Gabr report several possible extensions to the authors' study, including the introduction of a cutoff length to remove short pores and determining permeability directly from the network by simulating flow through individual pores within a selected domain. Discussions are followed by closure from the authors.}, number={4}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Atuahene, Frank and Chen, J. and Gabr, M. A. and Reddi, Lakshmi N. and Thangavadivelu, S.}, year={1999}, month={Apr}, pages={335–337} }
 @inproceedings{quaranta_gabr_sabodish_gates_ganz_1999, title={Well injection depth extraction (WIDE) for subsurface mixed waste flushing}, booktitle={Proceedings of the environmental industry partnerships conferences}, publisher={Morgantown, WV:  National Energy Technology Laboratory}, author={Quaranta, J. and Gabr, M. A. and Sabodish, M. and Gates, K. and Ganz, J.}, year={1999} }
 @article{gabr_dodson_1998, title={A study of stress distribution in geogrid reinforced sand}, volume={76}, journal={ASCE Geotechnical Special Publication}, author={Gabr, M. A. and Dodson, R.}, year={1998}, pages={62–76} }
 @article{gabr_akram_zayed_1998, title={Field versus laboratory filtration performance of a nonwoven geotextile with fly ash}, volume={16}, DOI={10.1016/s0266-1144(98)00009-0}, abstractNote={Long-term filtration behavior of a nonwoven geotextile with Class-F fly ash is investigated in the laboratory and in the field. The laboratory and field tests are conducted for approximately 1000 hours. Monitored data in the laboratory included flow rates and gradient ratio (GR) with time. Monitored data in the field included flow rate with time and the Biochemical Oxygen Demand (BOD5) of the effluent. Laboratory results indicated that the onset of the steady state stage commenced after 300 hours of flow with a steady state k of 3.5×10-6 m/s. Piping was evident from the increase in k accompanied by a decrease in the GR value. An initial GR value of 1.75 was reduced to a steady state value of approximately 0.75 after 300 hours. Initial piping was also observed from the field data as kfield initially increased with time. The k values from the GR tests compared favorably with the k value from the field test.}, number={4}, journal={Geotextiles and Geomembranes}, publisher={Elsevier BV}, author={Gabr, M.A. and Akram, M.H. and Zayed, Abla M.}, year={1998}, month={Aug}, pages={247–255} }
 @article{gabr_chen_thomas_1998, title={Kinetics of naphthalene flushing from sand/kaolinite soil using SDS surfactant}, volume={35}, number={6}, journal={Canadian Geotechnical Journal}, author={Gabr, M. A. and Chen, J. and Thomas, R.}, year={1998}, pages={976–985} }
 @article{gabr_chen_thomas_1998, title={Soil clogging during surfactant-enhanced flushing of naphthalene-contaminated sand-kaolinite}, volume={35}, DOI={10.1139/t98-054}, abstractNote={The removal of naphthalene from soils using a surfactant-enhanced flushing process was studied. Column tests were conducted on sand-kaolinite specimens (0, 5, and 20% kaolinite content) with water and sodium dodecylsulfate (SDS) surfactant used as permeants. Upon the introduction of surfactant, the hydraulic conductivity (k) of the various test specimens containing kaolinite decreased by up to two orders of magnitude but then recovered gradually to its initial value upon further flushing. Although more than 90% of the naphthalene contaminant was removed from the test soils, excessively long periods of flushing were needed due to the clogging phenomenon. Upon varying the concentration of the liquid constituents (SDS, naphthalene, and NaCl), the micellar solutions were observed to convert into phases including liquid crystals and gel. The viscosity of these phases was measured to range from 10 to 1000 cP. Several hydraulic conductivity tests conducted with SDS amended with NaCl indicated the alleviation of the reduction in k when sufficient NaCl concentration was used.Key words: surfactant, hydraulic conductivity, kaolinite, sand, naphthalene, SDS, contaminant, remediation, viscosity.}, number={6}, journal={Canadian Geotechnical Journal}, publisher={Canadian Science Publishing}, author={Gabr, M A and Chen, J and Thomas, R}, year={1998}, pages={976–985} }
 @article{gabr_chen_thomas_1998, title={Soil clogging during surfactant-enhanced flushing of naphthalene-contaminated sand-kaolinite}, volume={35}, DOI={10.1139/cgj-35-6-976}, abstractNote={The removal of naphthalene from soils using a surfactant-enhanced flushing process was studied. Column tests were conducted on sand-kaolinite specimens (0, 5, and 20% kaolinite content) with water and sodium dodecylsulfate (SDS) surfactant used as permeants. Upon the introduction of surfactant, the hydraulic conductivity (k) of the various test specimens containing kaolinite decreased by up to two orders of magnitude but then recovered gradually to its initial value upon further flushing. Although more than 90% of the naphthalene contaminant was removed from the test soils, excessively long periods of flushing were needed due to the clogging phenomenon. Upon varying the concentration of the liquid constituents (SDS, naphthalene, and NaCl), the micellar solutions were observed to convert into phases including liquid crystals and gel. The viscosity of these phases was measured to range from 10 to 1000 cP. Several hydraulic conductivity tests conducted with SDS amended with NaCl indicated the alleviation of the reduction in k when sufficient NaCl concentration was used.Key words: surfactant, hydraulic conductivity, kaolinite, sand, naphthalene, SDS, contaminant, remediation, viscosity.}, number={6}, journal={Revue canadienne de géotechnique}, publisher={Canadian Science Publishing}, author={Gabr, M.A. and Chen, J. and Thomas, R.}, year={1998}, pages={976–985} }
 @article{gabr_wang_zhao_1997, title={Buckling of Piles with General Power Distribution of Lateral Subgrade Reaction}, volume={123}, DOI={10.1061/(asce)1090-0241(1997)123:2(123)}, abstractNote={A model for evaluating the critical buckling capacity of long slender friction piles is developed with lateral soil support included based on the concept of the subgrade reaction. A general power distribution of the coefficient of the subgrade reaction (kh), with depth, is utilized in the model. The lateral force-deflection (P-y) behavior is assumed to be linear. A parametric study was conducted to demonstrate the effect of ω value, defining the distribution of the horizontal subgrade reaction, on the evaluated buckling capacity. In the case of the free top and fully embedded condition with embedment length (h) greater than 10 m, a 59% increase in the buckling capacity (Pcr) was predicted as ω was increased from 0 (constant horizontal subgrade reaction distribution) to 1 (linearly increasing horizontal subgrade reaction). Results also indicated that the boundary conditions at the pile tip have a minimal effect on Pcr when the nondimensional embedded length (h′) exceeded 3.3 for the free top, 5.6 for the f...}, number={2}, journal={Journal of Geotechnical and Geoenvironmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Wang, J. J. and Zhao, M.}, year={1997}, month={Feb}, pages={123–130} }
 @inbook{quaranta_gabr_szabo_bowders_1997, title={Characteristics and performance of prefabricated vertical drains for enhanced soil flushing}, volume={1596}, ISBN={0309061733}, DOI={10.3141/1596-14}, abstractNote={ The use of prefabricated vertical drains (PVDs) under vacuum conditions for soil flushing was investigated with soils consisting of 100 percent sand or a combination of 80 percent sand and 20 percent kaolinite. Tests of the 100 percent sand specimens indicated that the areal extent of the PVD zone of influence remained approximately 16 to 21 times the PVD-equivalent diameter (PVD circumference/π) as the extraction vacuum increased from 2.5 to 20 kPa. Tests of the sand kaolinite specimens (80/20 soil) indicated that the areal extent of the PVD zone of influence remained approximately 5 to 8 times the PVD equivalent diameter as the extraction vacuum increased from 2.5 to 20 kPa. The effective zone of influence in the 80/20 soil did not show a corresponding increase in areal extent as the vacuum pressure was increased beyond the PVD embedment depth. Pilot-scale tracer flushing tests demonstrated the feasibility of using PVDs for flushing 100 percent sand soil. The tracer testing demonstrated that longer flushing times were necessary to achieve 80 percent cleanup levels as the dry unit weights of soil increased from 1.57 to 1.67 g/cm3. The ratio of final to initial concentration reached 0.2 after flushing of the 1.57 g/cm3 soil for approximately 40 minutes. A similar ratio was reached after flushing of the 1.67 g/cm3 soil for 50 minutes. }, number={1}, booktitle={Pavements and structures monitoring, pavement instrumentation, and drainage systems evaluation}, publisher={Washington, DC: National Academy Press}, author={Quaranta, J. and Gabr, M. A. and Szabo, D. and Bowders, J. J.}, year={1997}, pages={93–100} }
 @article{akram_gabr_1997, title={Filtration of Fly Ash Using Nonwoven Geotextiles: Effect of Sample Preparation Technique and Testing Method}, volume={20}, DOI={10.1520/gtj19970001}, abstractNote={Abstract}, number={3}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Akram, M. H. and Gabr, M. A.}, year={1997}, month={Sep}, pages={GTJ19970001} }
 @article{quaranta_gabr_bowders_1997, title={First exposure performance of the bentonite component of a GCL in a low pH, calcium enriched environment, testing and acceptance criteria for geosynthetic clay liners}, volume={1308}, number={1}, journal={ASTM Special Technical Publications}, author={Quaranta, J. D and Gabr, M. A. and Bowders, J. J.}, year={1997}, pages={162–167} }
 @inproceedings{gabr_szabo_1997, title={PVDs zone of influence under vacuum in clayey soil}, volume={66}, booktitle={In situ remediation of the geoenvironment: Proceedings of the conference sponsored by the Geo-Institute and the Environmental Engineering Division of the American Society of Civil Engineers, Minneapolis, Minnesota, October 5-8, 1997 (Geotechnical special publication; no. 71)}, publisher={Reston, VA: American Society of Civil Engineers}, author={Gabr, M. A. and Szabo, D.}, year={1997}, pages={449–460} }
 @inproceedings{lowther_gabr_1997, title={Permeability and strength characteristics of urethane-grouted sand}, volume={66}, booktitle={Grouting: Compaction, remediation and testing: Proceedings of sessions sponsored by the Grouting Committee of the Geo-Institute of the American Society of Civil Engineers in conjuction with the Geo-Logan '97 Conference, Logan, Utah, July 16-18, 1997 (Geotechnical special publication; no. 66)}, publisher={New York: American Society of Civil Engineers}, author={Lowther, J. and Gabr, M. A.}, year={1997}, pages={258–270} }
 @inproceedings{ohrt_gabr_1997, title={Physical observations from shallow-buried explosive experiments in geogrid-reinforced earth}, ISBN={9780935803068}, booktitle={Geosynthetics '97 Conference proceedings}, publisher={St. Paul: Industrial Fabrics Association International}, author={Ohrt, A. P. and Gabr, M. A.}, year={1997} }
 @inproceedings{gabr_wang_kiger_1997, title={Pile buckling capacity and corresponding first modes}, booktitle={Mechanics Pan-America 1997 :selected and extended papers from the 5th Pan-American Congress of Applied Mechanics, January 1997, San Juan, Puerto Rico}, publisher={New York: American Society of Mechanical Engineers}, author={Gabr, M. A. and Wang, J. and Kiger, S. A.}, editor={L.A. Godoy, M. Rysz and Suarez, L.E.Editors}, year={1997} }
 @inproceedings{gabr_szabo_williamson_sabodish_1997, title={Subsurface flushing of BTEX using prefabricated vertical drains (PVDs) in clay}, volume={2}, number={6}, booktitle={Environment `97, International Conference on Environmental Management and Technologies}, author={Gabr, M. A and Szabo, D. and Williamson, A. and Sabodish, M.}, year={1997} }
 @inproceedings{gabr_freshwater_1997, title={Urethane grout for barrier formation in sand}, volume={14}, booktitle={Soil mechanics and foundation engineering, fourteenth international conference: Proceedings of the Fourteenth International Conference on Soil Mechanics and Foundation Engineering, Hamburg Germany, Sept. 1997}, author={Gabr, M. A. and Freshwater, J. S.}, year={1997}, pages={1903–1906} }
 @inproceedings{gabr_akram_1996, place={Lancaster, Pa.}, title={Clogging and piping criteria for geotextile filters with fly ash}, volume={1}, ISBN={9781566764629}, booktitle={Environmental geotechnology :proceedings of the 3rd International Symposium}, publisher={Technomic Pub. Co.}, author={Gabr, M. A. and Akram, M.}, editor={Inyang, H. I. and Fang, H.-Y.Editors}, year={1996}, pages={836–847} }
 @inproceedings{gabr_butler_1996, place={Lancaster, Pa.}, title={Development of fly ash-based low permeability flowable fill}, volume={1}, ISBN={9781566764629}, booktitle={Environmental geotechnology :proceedings of the 3rd International Symposium}, publisher={Technomic Pub. Co.}, author={Gabr, M. A. and Butler, C. S.}, editor={Inyang, H. I. and Fang, H.-Y.Editors}, year={1996}, pages={426–435} }
 @inproceedings{quaranta_gabr_szabo_hewes_cook_1996, title={Developments in prefabricated vertical drain enhanced soil flushing}, ISBN={9781880653289}, booktitle={The proceedings of the Seventh (1997) International Offshore and Polar Engineering Conference :presented at the Seventh (1996) International Offshore and Polar Engineering Conference held in Honolulu, USA, May 25-30, 1997 Offshore and Polar Engineers (ISO)}, publisher={Golden, CO: The Society}, author={Quaranta, J. D. and Gabr, M. A. and Szabo, D. and Hewes, K. and Cook, E. E.}, year={1996} }
 @article{gabr_boury_butler_1996, title={Fly ash-based mixtures for low permeability grouts  stabilized with lime sludge}, volume={14}, number={1}, journal={Geotechnical News}, author={Gabr, M. A. and Boury, E. M. and Butler, C.}, year={1996} }
 @article{gabr_bowders_wang_quaranta_1996, title={In situ soil flushing using prefabricated vertical drains}, volume={33}, ISSN={["0008-3674"]}, DOI={10.1139/t96-026}, abstractNote={ The use of prefabricated vertical drains (PVDs) for enhanced soil flushing was investigated using a bench scale experimental setup. Soil samples were prepared and saturated in contaminant recovery cells (CRC). The PVDs were installed in rectangular and circular configurations, and a vacuum was applied to recover subsurface water. A predictive model for contaminant transport using the PVD-enhanced soil flushing was developed and presented. Results from the CRC tests using four PVDs in a rectangular arrangement indicated that the volume of the retrieved fluid increased as a function of the vacuum level and was approximately 0.55 mL/s at a vacuum level of 9.0 kPa. This represented a recovery efficiency of approximately 100%, since the base inflow through the sample was 0.55 mL/s. Using six PVDs in a circular configuration with a spacing of 14 mm from the center of the circle, a flow rate of approximately 6 mL/s was recovered under 6.8 kPa of vacuum. The average drawdown under a vacuum of 8.6 kPa ranged from 15 to 45 mm, and the zone of effective drawdown was measured to be approximately 200 mm in diameter. This value is approximately 10 times the effective diameter of the PVDs. An injection–extraction test indicated that, under an applied injection pressure of 3.5 kPa, an injection flow rate of approximately 6.5 mL/s was measured. At a vacuum pressure of 6 kPa and using the cicular configuration, the injection and recovery flow rates were approximately balanced. Such balance is essential to avoid decreasing the flushing rate due to the compression of the soil voids as well as to avoid the desaturation of soil profile. }, number={1}, journal={CANADIAN GEOTECHNICAL JOURNAL}, publisher={Canadian Science Publishing}, author={Gabr, MA and Bowders, JJ and Wang, J and Quaranta, J}, year={1996}, month={Feb}, pages={97–105} }
 @inproceedings{gabr_freshwater_cook_1996, title={Injectability and durability of urethane as a permeation grout for subsurface containment of waste}, ISBN={9780894486142}, booktitle={Proceedings of the International Topical Meeting on Nuclear and Hazardous Waste Management-Spectrum '96 :August 18-23, 1996, Seattle, Washington}, publisher={La Grange Park, Ill. : American Nuclear Society}, author={Gabr, M. A. and Freshwater, J. S. and Cook, E. E.}, year={1996} }
 @inproceedings{gabr_thomas_cook_shoblom_1996, title={Kinetics of naphthalene removal from sand and kaolinite/sand soils using SDS surfactant}, ISBN={9781880653227}, booktitle={The proceedings of the Sixth (1996) International Offshore and Polar Engineering Conference :presented at the Sixth (1996) International Offshore and Polar Engineering Conference held in Los Angeles, USA, May 26-31, 1996}, publisher={Golden, Colo. : International Society of Offshore and Polar Engineers (ISOPE)}, author={Gabr, M. A. and Thomas, R. and Cook, E. E. and Shoblom, K.}, editor={J. Lafleur and Rollin, A. L.Editors}, year={1996} }
 @article{gabr_wang_bowders_1996, title={Model for Efficiency of Soil Flushing Using PVD-Enhanced System}, volume={122}, DOI={10.1061/(asce)0733-9410(1996)122:11(914)}, abstractNote={A predictive model for drain-enhanced soil flushing is developed and presented. Results from a parametric study indicate that, as the depth of the contaminated zone (H) increases, the time needed to attain 50% clean up level (t{sub 50}) increases. Results also indicated the sensitivity of the predicted contaminant concentrations to variations in the partition coefficient (K{sub d}) and radial and vertical dispersivity ({alpha}{sub r} and {alpha}{sub z}). For the case of {alpha}{sub z} = 1 m, t{sub 50} is evaluated equal to 42 h, while a t{sub 50} of 55 h is predicted for {alpha}{sub z} = 0.1 m. The estimated t{sub 50} increases from 37 h for {alpha}{sub r} = 10 m to 61 h for {alpha}{sub r} = 0.1 m. Analyses and results presented in this paper indicate the feasibility of using the proposed model to predict soil flushing rate using PVD-enhanced system.}, number={11}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Wang, J. and Bowders, J. J.}, year={1996}, month={Nov}, pages={914–919} }
 @inproceedings{gabr_akram_1996, title={Retention and permeation of fly ash using nonwoven geotextiles}, ISBN={9782553005619}, booktitle={Geofilters '96 :Comptes rendus}, publisher={Montreal: Ecole polytechnique}, author={Gabr, M. A. and Akram, M.}, editor={Lafleur, J. and Rollin, A. L.Editors}, year={1996} }
 @article{gabr_wolff_brizendine_taylor_1996, title={Underseepage analysis of levees on two-layer and three-layer foundation}, volume={18}, ISSN={["0266-352X"]}, DOI={10.1016/0266-352x(95)00024-5}, abstractNote={A simplified numerical model for the analysis of levee underseepage is developed and presented. Idealization of the subsurface hydrogeologic conditions was achieved using two-layer and three-layer representation of the flow domain. Data from Magnolia levee, located in Magnolia, Ohio, were used to demonstrate the model applicability by comparing exit hydraulic gradient (i) values from the simplified model to predictions from 2-D finite element analysis (FEA). Results from the simplified model indicated that i values were merely dependent on the ratio of the foundation permeability (Kfx) to the blanket permeability (Kby). The i values from the FEA closely matched those from the simplified model for Kfx/Kby ratios less than 2000 and assuming permeability anisotropic ratio (rk) = 1. Piezometer data from the Sny Island levee, located in Quincy, Illinois, were used to demonstrate the applicability of the three-layer model.}, number={2}, journal={COMPUTERS AND GEOTECHNICS}, publisher={Elsevier BV}, author={Gabr, MA and Wolff, TF and Brizendine, AL and Taylor, HM}, year={1996}, pages={85–107} }
 @inproceedings{gabr_quaranta_cook_1996, title={Vertical drains in geotechnical engineering: state of the art review}, ISBN={9781880653289}, booktitle={The proceedings of the Seventh (1997) International Offshore and Polar Engineering Conference :presented at the Seventh (1996) International Offshore and Polar Engineering Conference held in Honolulu, USA, May 25-30, 1997 Offshore and Polar Engineers (ISO)}, publisher={Golden, CO: The Society}, author={Gabr, M. A. and Quaranta, J. D. and Cook, E. E.}, year={1996} }
 @article{akram_gabr_1995, title={A Critical evaluation of the gradient ratio test: Discussion of paper by Fannin et al.}, volume={18}, number={3}, journal={ASTM Geotechnical Testing Journal}, author={Akram, M. and Gabr, M. A.}, year={1995}, pages={389–390} }
 @article{gabr_lunne_powell_1995, title={Closure to “ P‐y Analysis of Laterally Loaded Piles in Clay Using DMT” by M. A. Gabr, T. Lunne, and J. J. Powell}, volume={121}, DOI={10.1061/(asce)0733-9410(1995)121:9(682)}, number={9}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Lunne, T. and Powell, J. J.}, year={1995}, month={Sep}, pages={682–683} }
 @article{pincus_fannin_vaid_shi_1995, title={Closure to “Discussion on ‘A Critical Evaluation of the Gradient Ratio Test’ by M. H. Akram and M. A. Gabr” by R. Jonathan Fannin, Yoginder P. Vaid, and Yucheng Shi}, volume={18}, DOI={10.1520/gtj11010j}, number={3}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Pincus, HJ and Fannin, RJ and Vaid, YP and Shi, Y}, year={1995}, pages={389} }
 @article{monaco_marchetti_1995, title={Discussion of “ P‐y Analysis of Laterally Loaded Piles in Clay Using DMT” by M. A. Gabr, T. Lunne, and J. J. Powell}, volume={121}, DOI={10.1061/(asce)0733-9410(1995)121:9(680)}, number={9}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Monaco, Paola and Marchetti, Silvano}, year={1995}, month={Sep}, pages={680–682} }
 @article{pincus_akram_gabr_1995, title={Discussion on “A Critical Evaluation of the Gradient Ratio Test” by R. Jonathan Fannin, Yoginder P. Vaid, and Yucheng Shi}, DOI={10.1520/gtj11009j}, journal={Geotechnical Testing Journal}, author={Pincus, HJ and Akram, MH and Gabr, MA}, year={1995} }
 @inproceedings{gabr_thomas_szabo_quaranta_1995, title={Effect of SDS surfactant on the hydraulic conductivity of sand/kaolinite soils}, booktitle={X Panamerican Conference on Soil Mechanics and Foundation Engineering : October 29-November 03, 1995}, publisher={Mexico, D.F.: Sociedad Mexicana de Mecanica de Suelos}, author={Gabr, M. A. and Thomas, R. and Szabo, D. and Quaranta, J. D.}, year={1995} }
 @article{pincus_gabr_akram_taylor_1995, title={Effect of Simulated Roots on the Permeability of Silty Soils}, volume={118}, DOI={10.1520/gtj10127j}, abstractNote={Abstract}, number={1}, journal={ASTM Geotechnical Testing Journal}, publisher={ASTM International}, author={Pincus, HJ and Gabr, MA and Akram, M and Taylor, HM}, year={1995}, pages={112–116} }
 @article{gabr_bowders_shoblom_1995, title={Flushing of polycyclic aromatic hydrocarbons from soil using SDS surfactant}, volume={46}, number={2}, journal={Journal of Geotechnical Engineering}, author={Gabr, M. A. and Bowders, J. and Shoblom, K.}, year={1995}, pages={1321–1334} }
 @article{pincus_gabr_valero_1995, title={Geotechnical Properties of Municipal Solid Waste}, volume={18}, DOI={10.1520/gtj10324j}, abstractNote={Abstract}, number={2}, journal={Geotechnical Testing Journal}, publisher={ASTM International}, author={Pincus, HJ and Gabr, MA and Valero, SN}, year={1995}, pages={241} }
 @article{gabr_valero_1995, title={Geotechnical Properties of Solid Waste}, volume={18}, number={2}, journal={ASTM Geotechnical Testing Journal}, author={Gabr, M. A. and Valero, S. N.}, year={1995}, pages={241–251} }
 @article{gabr_boury_bowders_1995, title={Leachate characteristics of fly ash stabilized with lime sludge}, volume={1486}, number={12}, journal={Transportation Research Record}, author={Gabr, M. A. and Boury, E. M. and Bowders, J. J.}, year={1995}, pages={13–20} }
 @article{gabr_gray_taylor_1995, title={Nuclear gage tests on soils containing various sized}, volume={56}, journal={ASCE Geotechnical Special Publication}, author={Gabr, M. A. and Gray, C. A. and Taylor, H. M.}, year={1995}, pages={35–47} }
 @article{gabr_lunne_powell_1995, title={P-y analysis of laterally loaded piles in clay using DMT, closure}, volume={121}, number={9}, journal={Journal of Geotechnical Engineering}, author={Gabr, M. A. and Lunne, T. and Powell, J.}, year={1995}, pages={882–683} }
 @article{gabr_bowders_wokasien_1995, title={Prefabricated vertical drains (PVD) for enhanced soil flushing}, volume={46}, number={2}, journal={Journal of Geotechnical Engineering}, author={Gabr, M. A. and Bowders, J. and Wokasien, S.}, year={1995}, pages={1250–1264} }
 @article{sample preparation techniques for testing of nonwoven geotextiles with fly ash, sampling environmental media_1995, volume={1282}, journal={ASTM Special Technical Publications}, year={1995}, pages={376–388} }
 @article{bowders_gabr_1995, title={Strip drains for in situ clean up of contaminated fine grained soils}, volume={13}, number={3}, journal={Geotechnical News}, author={Bowders, J. J. and Gabr, M. A.}, year={1995}, pages={21–25} }
 @article{gabr_bowders_runner_1994, title={ASSESSMENT OF ACID MINE DRAINAGE REMEDIATION SCHEMES ON GROUND WATER FLOW REGIMES AT A RECLAIMED MINE SITE}, volume={1994}, DOI={10.21000/jasmr94020168}, number={2}, journal={Journal American Society of Mining and Reclamation}, publisher={American Society of Mining and Reclamation (ASMR)}, author={Gabr, M.A. and Bowders, J.J. and Runner, M. S.}, year={1994}, pages={168–177} }
 @inproceedings{gabr_bowders_runner_1994, title={Assessment of acid mine drainage remediation schemes on ground water flow regimes at a reclaimed mine site}, volume={2}, booktitle={Proceedings of the international land reclamation and mine drainage conference and third international conference on the abatement of acidic drainage}, author={Gabr, M.A. and Bowders, J.J. and Runner, M.S.}, year={1994}, pages={SP 06B–94} }
 @article{gabr_wang_1994, title={Buckling of Friction Piles Supporting Bridge Foundation}, volume={1447}, number={10}, journal={Transportation Research Record}, author={Gabr, M. A. and Wang, J.}, year={1994}, pages={93–101} }
 @inproceedings{gabr_wang_wokasien_1994, title={Contaminant transport model for soil flushing using prefabricated vertical drains (PVD)}, booktitle={Hazardous and industrial wastes : proceedings of the Twenty-sixth Mid-Atlantic Industrial Waste Conference: August 7-10, 1994, University of Delaware, Newark, DE}, publisher={Lancaster, Pa. :  Technomic Pub. Co.}, author={Gabr, M. A. and Wang, J. and Wokasien, S.}, year={1994} }
 @article{gabr_bordon_1994, title={Data Acquisition System and Computer Control of Calibration Chamber Tests on Sand}, volume={1432}, number={10}, journal={Transportation Research Record}, author={Gabr, M. A. and Bordon, R. H.}, year={1994}, pages={18–25} }
 @article{bowders_gabr_boury_baker_1994, title={ENGINEERING EVALUATION OF AMENDED FLY ASH FOR HYDRAULIC BARRIERS}, volume={1994}, DOI={10.21000/jasmr94020226}, abstractNote={A laboratory investigation was conducted to determine the potential for producing low-hydraulic conductivity (k<lo• 7 cm/s), amended fly ash barriers.The objective is to control sources of water which now leach and transport products of oxidization from mine spoil and overburden materials --the result of which is acidic drainage.The surface barrier evaluation program consisted of blending a Class F fly ash, clay and sand at varying dry weight percentages and water contents and analyzing the resulting mixtures' physical and engineering properties.Optimum water content for the mixes ranged from 16.7% for 10% clay to 13. 8% for 30% clay.Specimens were prepared at water contents from approximately -4% to +4% of optimum for each mix ratio.Over this range, the hydraulic conductivity typically varied by one order of magnitude.The lowest hydraulic conductivity achieved during the project was 1.5x10• 7 cm/s for a mix containing 40% fly ash, 30% clay, and 30% sand.}, number={2}, journal={Journal American Society of Mining and Reclamation}, publisher={American Society of Mining and Reclamation (ASMR)}, author={Bowders, John J. and Gabr, Mo A. and Boury, Ellis M. and Baker, Robert}, year={1994}, pages={226–233} }
 @article{gabr_wang_kiger_1994, title={Effect of Boundary Conditions on Buckling of Friction Piles}, volume={120}, DOI={10.1061/(asce)0733-9399(1994)120:6(1392)}, abstractNote={In practice, evidence suggests that long, slender piles subjected to axial loads can fail under axial stresses below the yield point of the pile material. A general solution for critical buckling capacity of long, slender friction piles in clay is presented using the minimum potential energy method. The Rayleigh-Ritz method is adopted to select deflection functions satisfying six geometric boundary conditions encountered in practice. Parameter studies were performed to investigate the buckling response of fully and partially embedded piles and the effect of pile-top and tip conditions on buckling capacity. Results indicated that the boundary conditions at the pile tip have no effect on the critical buckling capacity in cases in which the nondimensional embedment length (\Ih\N’) exceeded a critical value. In addition, for fully embedded piles, the effect of embedment length was nearly negligible after \Ih\N’ exceeded a value of 6 for fixed-with-sway pile-top conditions.}, number={6}, journal={Journal of Engineering Mechanics}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A. and Wang, Jibai and Kiger, Sam A.}, year={1994}, month={Jun}, pages={1392–1400} }
 @inproceedings{gabr_bowders_boury_1994, title={Fly Ash/Sludge Grout for Abatement of AMD}, volume={2}, booktitle={The 3rd International Conference on the Abatement of Acid Mine Drainage}, author={Gabr, M. and Bowders, J. and Boury, E.}, year={1994}, month={Apr}, pages={168–177} }
 @inproceedings{bowders_gabr_runner_1994, title={Groundwater Modeling Analysis of Acid Mine Drainage Remediation Schemes}, volume={2}, booktitle={The Third International Conference on the Abatement of Acid Mine Drainage}, author={Bowders, J. and Gabr, M. and Runner, M.}, year={1994}, month={Apr}, pages={226–233} }
 @inproceedings{akram_gabr_head_1994, title={Low cement stabilization of fly ash/scrubber sludge grout for engineering applications}, booktitle={Hazardous and industrial wastes : proceedings of the Twenty-sixth Mid-Atlantic Industrial Waste Conference: August 7-10, 1994, University of Delaware, Newark, DE}, publisher={Lancaster, Pa. :  Technomic Pub. Co.}, author={Akram, M. and Gabr, M. A. and Head, W.}, year={1994}, pages={567–574} }
 @article{gabr_lunne_powell_1994, title={P-y Analysis of Laterally Loaded Piles in Clay Using DMT}, volume={120}, DOI={10.1061/(asce)0733-9410(1994)120:5(816)}, abstractNote={A discussion of a paper with the aforementioned title by Gabr, Lunne, and Powell, published in this journal (Volume 120, Number 5, May 1994), is presented. Discussers Monaco and Marchetti concentrate on four issues related to P-y analysis of laterally loaded piles using dilatometer tests: 1) computer deflection by the authors' model overestimates the measured deflections at large loads and underestimates the measured deflections at lower loads; 2) strength reduction factors as a function of overconsolidation ratio are "too severe"; 3) the link between the coefficient, or constant, of subgrade reactions; 4) the authors' statement "Mathematically, the minimum value to satisfy (3) is 6.5" is objectionable. Discussion is followed by closure from the authors.}, number={5}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, M. A. and Lunne, T. and Powell, J. J.}, year={1994}, month={May}, pages={816–837} }
 @article{gabr_bowders_mooney_1994, title={Settlement analysis of landfill liners over deep mined areas}, volume={40}, number={1}, journal={Journal of Geotechnical Engineering}, author={Gabr, M. A. and Bowders, J. J. and Mooney, D. T.}, year={1994}, pages={436–450} }
 @inproceedings{gabr_g._1994, title={Simplified model for evaluation of tensile strains in liner systems over subsurface cavities}, booktitle={Hazardous and industrial wastes : proceedings of the Twenty-sixth Mid-Atlantic Industrial Waste Conference: August 7-10, 1994, University of Delaware, Newark, DE}, publisher={Lancaster, Pa. :  Technomic Pub. Co.}, author={Gabr, M. A. and G., Awaad}, year={1994}, pages={42–52} }
 @article{gabr_hunter_1994, title={Stress-strain analysis of geogrid-supported liners over subsurface cavities}, volume={12}, DOI={10.1007/bf00429767}, number={2}, journal={Geotechnical and Geological Engineering}, publisher={Springer Nature}, author={Gabr, M. A. and Hunter, T. J.}, year={1994}, month={Jun}, pages={65–86} }
 @inproceedings{gabr_akram_1994, title={Study of clogging behavior of nonwoven geotextiles with fly ash using gradient ratio tests}, booktitle={Hazardous and industrial wastes : proceedings of the Twenty-sixth Mid-Atlantic Industrial Waste Conference: August 7-10, 1994, University of Delaware, Newark, DE}, publisher={Lancaster, Pa. :  Technomic Pub. Co.}, author={Gabr, M. A. and Akram, M.}, year={1994}, pages={34–42} }
 @article{gabr_aas_wang_1993, title={3-D deformation analysis of pile groups during wave loading}, volume={38}, journal={ASCE Geotechnical Special Publication}, author={Gabr, M. A. and Aas, P. M. and Wang, J.}, year={1993}, pages={109–126} }
 @book{berg_reed_gabr_1993, title={A systematic assessment of the state of hazardous waste clean-up technologies. Quarterly technical progress report, April 1--June 30, 1993}, DOI={10.2172/10117545}, abstractNote={West Virginia University (WVU) and the US DOE Morgantown Energy Technology Center (METC) entered into a Cooperative Agreement on August 29, 1992 entitled ``Decontamination Systems Information and Research Programs.`` Stipulated within the Agreement is the requirement that WVU submit to METC a series of Technical Progress Report for Year 1 of the Agreement. This report reflects the progress and/or efforts performed on the following nine technical projects encompassed by the Year 1 Agreement for the period of April 1 through June 30, 1993: Systematic assessment of the state of hazardous waste clean-up technologies; site remediation technologies -- drain-enhanced soil flushing (DESF) for organic contaminants removal; site remediation technologies -- in situ bioremediation of organic contaminants; excavation systems for hazardous waste sites; chemical destruction of polychlorinated biphenyls; development of organic sensors -- monolayer and multilayer self-assembled films for chemical sensors; Winfield lock and dam remediation; Assessments of Technologies for hazardous waste site remediation -- non-treatment technologies and pilot scale test facility implementation; and remediation of hazardous sites with stream reforming.}, institution={Office of Scientific and Technical Information (OSTI)}, author={Berg, M.T. and Reed, B.E. and Gabr, M.}, year={1993}, month={Jul} }
 @inproceedings{gabr_collin_1993, title={Analysis of landfill liner system on a foundation with an infinitely long void}, ISBN={9780935803013}, booktitle={Geosynthetic liner systems :innovations, concerns, and designs}, publisher={St. Paul, MN: Industrial Fabrics Association International}, author={Gabr, M. A. and Collin, J. G.}, editor={R.M. Koerner and Wilson-Fahmy, R.F.Editors}, year={1993} }
 @article{gabr_1993, title={Discussion of “
            <i>Model for Capacity of Single Piles in Sand Using Fuzzy Sets
            ” by C. H. Juang, J. L. Wey, and D. J. Elton (December, 1991, Vol. 117, No. 12)}, volume={119}, ISSN={0733-9410 1944-8368}, url={http://dx.doi.org/10.1061/(asce)0733-9410(1993)119:1(191)}, DOI={10.1061/(asce)0733-9410(1993)119:1(191)}, number={1}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A.}, year={1993}, month={Jan}, pages={191–193} }
 @article{gabr_1993, title={Discussion of “ Analysis of Laterally Loaded Shafts in Rock ” by John P. Carter and Fred H. Kulhawy (June, 1992, Vol. 118, No. 6)}, volume={119}, DOI={10.1061/(asce)0733-9410(1993)119:12(2015)}, number={12}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A.}, year={1993}, pages={2015–2018} }
 @inproceedings{bowders_gabr_hunter_mooney_1992, title={Analysis of a landfill over a deep mined Area: A Case Study}, booktitle={Surface subsidence due to underground mining :  3rd Workshop}, publisher={Morgantown :  West Virginia University}, author={Bowders, J. J. and Gabr, M. A. and Hunter, T-J. and Mooney, D. T.}, year={1992}, pages={146–157} }
 @article{gabr_borden_1992, title={Closure to “ Lateral Analysis of Piers Constructed on Slopes ” by Mohammed A. Gabr and Roy H. Borden (December, 1990, Vol. 116, No. 12)}, volume={118}, DOI={10.1061/(asce)0733-9410(1992)118:6(970.2)}, number={6}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A. and Borden, Roy H.}, year={1992}, month={Jun}, pages={970–971} }
 @article{dilatometer soil parameters for analysis of piles in clay_1992, volume={186}, journal={Publikasjon/Norges geotekniske institutt = Publication/Norwegian Geotechnical Institute}, year={1992} }
 @article{hovland_1992, title={Discussion of “ Lateral Analysis of Piers Constructed on Slopes ” by Mohammed A. Gabr and Roy H. Borden (December, 1990, Vol. 116, No. 12)}, volume={118}, DOI={10.1061/(asce)0733-9410(1992)118:6(969)}, number={6}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Hovland, H. John}, year={1992}, month={Jun}, pages={969–970} }
 @article{gabr_bordon_1992, title={Laterally Loaded Piers Constructed in Slopes; closure}, volume={118}, number={6}, journal={Journal of Geotechnical Engineering}, author={Gabr, M. A. and Bordon, R. H.}, year={1992}, pages={969–970} }
 @inproceedings{gabr_wantalnd_1992, title={Overview of landfill design practice}, booktitle={Hazardous and industrial wastes:  proceedings of the Twenty-fourth Mid-Atlantic Industrial Waste Conference}, publisher={Lancaster, Pa. : Technomic Pub. Co.}, author={Gabr, M. A. and Wantalnd, G. M.}, editor={Brian E. Reed and Sack, William A.Editors}, year={1992} }
 @inproceedings{gabr_hunter_collin_1992, title={Stability of geogrid-reinforced landfill liners over sinkholes}, ISBN={9789054100935}, booktitle={Earth reinforcement practice :proceedings of the International Symposium on Earth Reinforcement Practice, Fukuoka, Kyushu, Japan, 11-13 November 1992}, publisher={Brookfield, VT: A.A. Balkema}, author={Gabr, M. A. and Hunter, T-J. and Collin, J. G.}, editor={H. Ochiai, S. Hayashi and Otani, J.Editors}, year={1992} }
 @article{collin_gabr_mackinnon_1992, title={Timber crib-faced soil-nailed retaining wall}, volume={31}, number={2}, journal={Journal of Geotechnical Engineering}, author={Collin, J. G. and Gabr, M. A. and Mackinnon, A. G.}, year={1992}, pages={1457–1463} }
 @inproceedings{gabr_lunne_mokkelbost_powell_1991, title={Dilatometer Soil Parameters for Analysis of Piles in Clay}, booktitle={Proceedings of the 10th European Conference on Soil Mechanics and Foundation}, author={Gabr, M.A. and Lunne, Tom and Mokkelbost, Karl and Powell, John}, year={1991}, month={May}, pages={403–406} }
 @article{gabr_borden_1991, title={Lateral analysis of piers constructed on slopes}, volume={28}, DOI={10.1016/0148-9062(91)90959-p}, abstractNote={This paper presents a model to evaluate P, which is used in the fourmulation of P-y curves (soil-pier load-deflection characteristis) for rigid piers constructed in cohesionless soils and in soils that possess both friction and cohesion with sloping ground surfaces. A 3-dimensional wedge equilibrium analysis is used to fourmulate the model, taking into account the influence of sloping ground surface. A parametric study is conducted to demonstrate the significance of including the slope effect on the lateral behavior of piers. Also presented are the results of five load tests.}, number={4}, journal={International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts}, publisher={Elsevier BV}, author={Gabr, M.A. and Borden, R.H.}, year={1991}, month={Jul}, pages={A244} }
 @article{borden_gabr_1991, title={Lateral response of rigid piers in sand, clay, and layered profiles}, volume={1331}, number={1}, journal={Transportation Research Record}, author={Borden, R. H. and Gabr, M. A.}, year={1991}, pages={79–86} }
 @article{kulatilake_lacasse_gabr_1991, title={Probabilistic equivalent linear soil spring stiffness analysis for gravity platforms: Illustrative example}, volume={12}, DOI={10.1016/0266-352x(91)90010-d}, abstractNote={The companion paper [1] suggests a procedure to perform equivalent linear soil spring stiffness analysis for gravity platforms founded on clay and loaded under undrained conditions. This paper provides an example to illustrate the suggested procedure. The CONDEEP SP4-10-24 platform concept proposed for the Troll field was used for the example. Plastic Drammen clay was chosen as the foundation soil to a depth of 150 m. Wave loads on the platform were estimated assuming a 70 yr platform life, plus an 18 hr storm build-up, plus a 6 hr storm with a return period of 100 yrs. The constitutive model for the soil was calculated for the 6 hr rare event in the load history, assuming that the rare even occurs at the end of the load history. The coefficients of variation of the equivalent soil spring stiffnesses (horizontal and rotational) were found to be around 0.50.}, number={1}, journal={Computers and Geotechnics}, publisher={Elsevier BV}, author={Kulatilake, Pinnaduwa H.S.W. and Lacasse, Suzanne and Gabr, Mohammed}, year={1991}, month={Jan}, pages={29–54} }
 @article{smith_gabr_kula_1991, title={Soil-rock transition: uncertainties related to design and construction}, volume={29}, number={1}, journal={Journal of Geotechnical Engineering}, author={Smith, R. E. and Gabr, M. A. and Kula, J. R.}, year={1991}, pages={91–106} }
 @article{gabr_borden_1990, title={Lateral Analysis of Piers Constructed on Slopes}, volume={116}, DOI={10.1061/(asce)0733-9410(1990)116:12(1831)}, abstractNote={A force‐equilibrium model was used to derive a theoretical solution for the lateral capacity of rigid piers embedded in cohesionless and c‐ϕ soil profiles having sloping ground surfaces. A parametric study indicated that the amount of reduction due to the slope presence is dependent on the value of the ground‐surface slope angle θ and the soil‐strength properties. The ultimate resistance‐reduction factor ε is presented as a function of the soil properties and the slope angle θ. The developed slope model is validated using the results of five full‐scale pier‐load tests. The angle μ, which defines the size of the displaced wedge in front of the pier, was assumed equal to ϕ/2 for predictions that both accounted for and ignored the slope presence. In addition, predictions were carried out using angle ft corresponding to minimum‐resistance wedge. Accounting for the slope effect, predicted capacities were within 15‐25% of the measured capacities. On the other hand, predictions made ignoring the presence of the slope overpredicted the measured capacities by as much as 50%.}, number={12}, journal={Journal of Geotechnical Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gabr, Mohammed A. and Borden, Roy H.}, year={1990}, pages={1831–1850} }
 @article{laterally loaded piers constructed in slopes_1990, volume={116}, number={12}, journal={Journal of Geotechnical Engineering}, year={1990}, pages={1831–1850} }
 @inproceedings{gabr_borden_1989, title={Influence of sloping surface on lateral load-deflection response of rigid piers}, ISBN={9789061918905}, booktitle={Proceedings of the twelfth international conference on soil mechanics and foundation engineering, Rio de Janeiro/13-18 August 1989}, publisher={Brookfield, VT: A.A. Balkema}, author={Gabr, M. A. and Borden, R. H.}, year={1989} }
 @inproceedings{nadim_gabr_hansen_1989, title={Sensitivity study of the cyclic axial capacity of a single pile}, ISBN={9780872627048}, booktitle={Foundation engineering :current principles and practices : proceedings of the congress, Evanston, Illinois, June 25-29, 1989}, publisher={New York, N.Y. : The Society}, author={Nadim, F. and Gabr, M. A. and Hansen, B.}, year={1989} }
 @inproceedings{gabr_borden_1988, title={Analysis of load deflection response of laterally loaded piers using DMT}, ISBN={9789061918011}, booktitle={Penetration testing, 1988 :proceedings of the First International Symposium on Penetration Testing, ISOPT-1, Orlando, 20-24 March 1988}, publisher={Brookfield, VT: A.A. Balkema}, author={Gabr, M. A. and Borden, R. H.}, year={1988} }
 @article{gabr_borden_1988, title={LTBASE: Lateral analysis of piers including base and slope effects: Program documentation}, volume={1169}, number={4}, journal={Transportation Research Record}, author={Gabr, M. A. and Borden, R. H.}, year={1988}, pages={83–93} }
 @inproceedings{gabr_1986, title={Earthquake induced settlement of dry sand}, ISBN={9780943198071}, booktitle={Proceedings of the 3rd U.S. National Conference on Earthquake Engineering :August 24-28, 1986, Charleston, South Carolina}, publisher={Berkeley, Ca.: EERI}, author={Gabr, M. A.}, year={1986} }
 @inproceedings{gabr_borden_1986, title={Influence of Base Resistance on the Lateral Load-Deflection Behavior of Rigid Piers in Sand}, booktitle={Proceedings of the First International Conference on Soil-Structure Interaction}, author={Gabr, M.A. and Borden, Roy H.}, year={1986}, month={May}, pages={219–226} }
 @article{motan_gabr_1985, title={Flat dilatometer and lateral soil modulus}, volume={1022}, journal={Transportation Research Record}, author={Motan, S. and Gabr, M. A.}, year={1985}, pages={37–47} }
 @inproceedings{motan_gabr_1984, title={A Flat dilatometer study of lateral soil response}, ISBN={9780872624276}, booktitle={Analysis and design of pile foundations :proceedings of a symposium sponsored by the ASCE Geotechnical Engineering Division and a session sponsored by the ASCE Technical Council on Codes and Standards in conjunction with the ASCE National Convention, San Francisco, California, October 1-5, 1984}, publisher={New York, N.Y. : American Society of Civil Engineers}, author={Motan, S. and Gabr, M. A.}, year={1984} }
 @article{quaranta_gabr_bowders, title={First-Exposure Performance of the Bentonite Component of a GCL in a Low-pH, Calcium-Enriched Environment}, DOI={10.1520/stp11801s}, abstractNote={Testing was conducted on the bentonite portion of a Geosynthetic Clay Liner (GCL) for application to an environment characterized as having high concentrations of dissolved calcium ions. This environment presents conditions that might affect the long-term hydraulic function of the GCL as a component in a barrier system. Experiments were conducted to investigate first-exposure compatibility of a sodium bentonite GCL subject to the affects of acidic groundwater and second from the combined affects of acidic groundwater enriched with calcium. Relationships between the ionic exchange of sodium, potassium, magnesium and calcium species in the bentonite, and changes in hydraulic conductivity and electrical conductance are reported and discussed.}, journal={Testing and Acceptance Criteria for Geosynthetic Clay Liners}, publisher={ASTM International}, author={Quaranta, JD and Gabr, MA and Bowders, JJ}, pages={162–162-16} }