@article{nafisi_montoya_evans_2020, title={Shear Strength Envelopes of Biocemented Sands with Varying Particle Size and Cementation Level}, volume={146}, ISSN={["1943-5606"]}, DOI={10.1061/(ASCE)GT.1943-5606.0002201}, abstractNote={AbstractMicrobial-induced calcium carbonate precipitation (MICP) is a bio-mediated technique that may be used to improve the strength and stiffness of soils. Various parameters affect the behavior ...}, number={3}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, author={Nafisi, Ashkan and Montoya, Brina M. and Evans, T. Matthew}, year={2020}, month={Mar} }
 @article{cunningham_evans_tayebali_2013, title={Gradation effects on the mechanical response of crushed stone aggregate}, volume={14}, ISSN={["1477-268X"]}, DOI={10.1080/10298436.2012.690518}, abstractNote={A study was conducted to evaluate the effects of varying the gradation of aggregate base course (ABC) on material performance. Five different gradations consistent with a range of common ABC were selected. Experimental trials were performed to classify the materials and assess the performance differences between the five gradations. The gradation was found to affect the behaviour of the aggregate in that coarser gradations gave better strength and resilience values under conditions most similar to those found in the field. From research and experience during the laboratory testing, it was concluded that the coarsest blends became too difficult to realistically work with and they also lacked the stability of the well-graded combinations. It was also observed that as the amount of fines in the specimens exceeded 8–12% by mass, the fines governed the behaviour of the material. Results are interpreted using previously published work on specific surface, ‘ideal’ gradations and micromechanical models for the response of granular materials.}, number={3}, journal={INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING}, author={Cunningham, Charles N. and Evans, T. Matthew and Tayebali, Akhtar A.}, year={2013}, month={Apr}, pages={231–241} }
 @article{kress_yun_narsilio_evans_lee_2012, title={Evaluation of hydraulic conductivity in 3D random and heterogeneous particulate materials using network model}, volume={40}, ISSN={["1873-7633"]}, DOI={10.1016/j.compgeo.2011.09.007}, abstractNote={In this study we present a three-dimensional network model for the evaluation of hydraulic conductivity using new pore structure characterization algorithms. We define a porous medium from the sphere packing generated by discrete element method (DEM). The network model is based on connectivity of pore chambers linked along discretized pathway using a harmonic mean radius value computed from a series of radius-varying tubes that represent the irregularly shaped pore channel. Particle packing cases under investigation include regular packings, monodispersed, and polydispersed cases with varying porosity. Finite element analysis is implemented to obtain hydraulic conductivity values for regular packing cases for comparison. Laboratory experimentation results corroborate numerically obtained values with good agreement. Observations show the pore space should be tessellated once pore chambers are established in order to preserve the geometrical uniqueness of randomly shaped pore channel, avoid redundancy, and minimize pore channel overlap. Also, it is observed that limits must be defined for the total number of grains needed for representativeness and discretization density for the quantification of random heterogeneous pore structure.}, journal={COMPUTERS AND GEOTECHNICS}, author={Kress, Jeremy and Yun, Tae Sup and Narsilio, Guillermo A. and Evans, T. Matthew and Lee, Dae-Soo}, year={2012}, month={Mar}, pages={45–52} }
 @article{andrade_chen_le_avila_evans_2012, title={On the rheology of dilative granular media: Bridging solid- and fluid-like behavior}, volume={60}, ISSN={["0022-5096"]}, DOI={10.1016/j.jmps.2012.02.011}, abstractNote={A new rate-dependent plasticity model for dilative granular media is presented, aiming to bridge the seemingly disparate solid- and fluid-like behavioral regimes. Up to date, solid-like behavior is typically tackled with rate-independent plasticity models emanating from Mohr–Coulomb and Critical State plasticity theory. On the other hand, the fluid-like behavior of granular media is typically treated using constitutive theories amenable to viscous flow, e.g., Bingham fluid. In our proposed model, the material strength is composed of a dilation part and a rate-dependent residual strength. The dilatancy strength plays a key role during solid-like behavior but vanishes in the fluid-like regime. The residual strength, which in a classical plasticity model is considered constant and rate-independent, is postulated to evolve with strain rate. The main appeal of the model is its simplicity and its ability to reconcile the classic plasticity and rheology camps. The applicability and capability of the model are demonstrated by numerical simulation of granular flow problems, as well as a classical shear banding problem, where the performance of the continuum model is compared to discrete particle simulations and physical experiment. These results shed much-needed light onto the mechanics and physics of granular media at various shear rates.}, number={6}, journal={JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS}, author={Andrade, Jose E. and Chen, Qiushi and Le, Phong H. and Avila, Carlos F. and Evans, T. Matthew}, year={2012}, month={Jun}, pages={1122–1136} }
 @article{yun_evans_2011, title={Evolution of at-rest lateral stress for cemented sands: experimental and numerical investigation}, volume={13}, ISSN={["1434-7636"]}, DOI={10.1007/s10035-011-0279-y}, number={5}, journal={GRANULAR MATTER}, author={Yun, Tae Sup and Evans, T. Matthew}, year={2011}, month={Oct}, pages={671–683} }
 @article{patil_valdes_evans_2011, title={Swell Mitigation with Granulated Tire Rubber}, volume={23}, ISSN={["1943-5533"]}, DOI={10.1061/(asce)mt.1943-5533.0000229}, abstractNote={Experiments were conducted to investigate the odometric swell behavior of expansive soil specimens mixed independently with two different granular additives: silica sand and granulated tire rubber (GTR). All specimens were prepared with the same global water content. However, specimens that contained sand swelled less than did analogous specimens that contained GTR, regardless of the surcharge stress imposed before inundation. Phase relationship analyses based on "oversize correction" equations derived for mixtures with three solid phases indicate that the specimens possessed clay portions with different dry density and initial water content. Such differ- ences are attributed mainly to the role of additive grain stiffness during specimen preparation. Results from complementary discrete element method simulations indicate that the stiffness of the additive grains may also play a role in mitigating the swell via contact force alterations upon swell. DOI: 10.1061/(ASCE)MT.1943-5533.0000229. © 2011 American Society of Civil Engineers. CE Database subject headings: Concrete admixtures; Bentonite; Expansive soils; Rubber; Sand, material; Swelling, material. Author keywords: Additives; Bentonite; Expansive soil; Rubber; Sand; Swell.}, number={5}, journal={JOURNAL OF MATERIALS IN CIVIL ENGINEERING}, author={Patil, Ujwal and Valdes, Julio R. and Evans, T. Matthew}, year={2011}, month={May}, pages={721–727} }
 @article{evans_valdes_2011, title={The microstructure of particulate mixtures in one-dimensional compression: numerical studies}, volume={13}, ISSN={["1434-5021"]}, DOI={10.1007/s10035-011-0278-z}, number={5}, journal={GRANULAR MATTER}, author={Evans, T. Matthew and Valdes, Julio R.}, year={2011}, month={Oct}, pages={657–669} }
 @article{evans_frost_2010, title={Multiscale investigation of shear bands in sand: Physical and numerical experiments}, volume={34}, ISSN={["0363-9061"]}, DOI={10.1002/nag.877}, abstractNote={Abstract}, number={15}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS}, author={Evans, T. Matthew and Frost, J. David}, year={2010}, month={Oct}, pages={1634–1650} }
 @article{yun_evans_2010, title={Three-dimensional random network model for thermal conductivity in particulate materials}, volume={37}, ISSN={["0266-352X"]}, DOI={10.1016/j.compgeo.2010.08.007}, abstractNote={This paper describes a three-dimensional random network model to evaluate the thermal conductivity of particulate materials. The model is applied to numerical assemblies of poly-dispersed spheres generated using the discrete element method (DEM). The grain size distribution of Ottawa 20–30 sand is modeled using a logistic function in the DEM assemblies to closely reproduce the gradation of physical specimens. The packing density and inter-particle contact areas controlled by confining stress are explored as variables to underscore the effects of micro- and macro-scales on the effective thermal conductivity in particulate materials. It is assumed that skeletal structure of 3D granular system consists of the web of particle bodies interconnected by thermal resistor at contacts. The inter-particle contact condition (e.g., the degree of particle separation or overlap) and the particle radii determine the thermal conductance between adjacent particles. The Gauss–Seidel method allows evaluation of the evolution of temperature variation in the linear system. Laboratory measurements of thermal conductivity of Ottawa 20–30 sand corroborate the calculated results using the proposed network model. The model is extended to explore the evolution of thermal conduction depending on the nucleation habits of secondary solid phase as an anomalous material in the pore space. The proposed network model highlights that the coordination number, packing density and the inter-particle contact condition are integrated together to dominate the heat transfer characteristics in particulate materials, and allows fundamental understanding of particle-scale mechanism in macro-scale manifestation.}, number={7-8}, journal={COMPUTERS AND GEOTECHNICS}, author={Yun, Tae Sup and Evans, T. Matthew}, year={2010}, month={Nov}, pages={991–998} }
 @article{frost_evans_2009, title={Membrane Effects in Biaxial Compression Tests}, volume={135}, ISSN={["1090-0241"]}, DOI={10.1061/(ASCE)GT.1943-5606.0000011}, abstractNote={The effects of the confining membrane in laboratory tests on soil specimens have been the subject of numerous experimental, analytical, and numerical studies over the past half-century. This technical note expands the existing knowledge base by presenting a methodology and the associated results from an experimental study that has quantified the effect of the confining membrane in biaxial shear tests conducted on medium sand. The applicability of the method of biaxial tests on clay specimens is also presented. The results show that for both tests on sands and clays, the effect of the membrane on the shear stress on the failure plane are significant and should be accounted for in the interpretation of biaxial shear test results where localization occurs.}, number={7}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, author={Frost, J. David and Evans, T. Matthew}, year={2009}, month={Jul}, pages={986–991} }
 @article{evans_chall_zhao_rhyne_2009, title={Visualization and analysis of microstructure in three-dimensional discrete numerical models}, volume={23}, DOI={10.1061/(ASCE)0887-3801(2009)23:5(277)}, abstractNote={A computer program has been developed to allow for the virtual slicing of irregularly spaced and irregularly shaped three-dimensional image data. The program was used to virtually slice three-dimensional particle assemblies from discrete element method (DEM) simulations, allowing, for the first time, direct comparison to two-dimensional slices extracted from solidified physical specimens. Based on slices obtained from the numerical specimens, it is possible to compare quantitatively numerical microstructure directly to its physical analog, which should lead to greatly improved calibrations of granular mechanics models, and could facilitate the calibration of models across all scales of interest rather than solely at specimen boundaries. Improved confidence in the ability of the DEM to realistically simulate the microstructure of granular assemblies (through improved multiscale calibration) should result in increased confidence in microstructural parameters measurable in numerical simulations but inaccessible in the laboratory. Algorithm development within the framework of the open-source Visualization Toolkit is described and performance of the algorithm is quantified for two platforms. Results from virtual slices of a test assembly with regular particle packing are verified against known analytical solutions. A slice of a more complex assembly comprised of nearly 40,000 spheres is quantified statistically and compared to an analogous slice from a physical specimen of uniform sand.}, number={5}, journal={Journal of Computing in Civil Engineering}, author={Evans, T. M. and Chall, S. and Zhao, X. L. and Rhyne, T. M.}, year={2009}, pages={277–287} }
 @article{valdes_evans_2008, title={Sand-rubber mixtures: Experiments and numerical simulations}, volume={45}, ISSN={["0008-3674"]}, DOI={10.1139/T08-002}, abstractNote={This paper documents the results of laboratory experiments and numerical simulations conducted to examine the behavior of mixtures composed of rubber and sand particles of similar size. Emphasis was placed on assessing the role of loading type on the load-deformation behavior and selecting appropriate parameters for the discrete element modeling of sand–rubber, with relevance to the use of compressible particulate systems for filtration control. Experimental results show that sand–rubber exhibits load–unload hysteresis and residual strains post-unloading due to particle–particle and particle–wall locking effects that arise from sidewall friction. It is shown that the discrete element modeling of sand–rubber requires unconventional schemes because of the stiffness contrast between sand grains and rubber grains. The results have implications in the design of compressible particulate systems for seepage and filtration control and in the development of prediction tools for the field performance soil–rubber, which is finding increased usage in geotechnical and civil engineering infrastructures.}, number={4}, journal={CANADIAN GEOTECHNICAL JOURNAL}, author={Valdes, Julio R. and Evans, T. Matthew}, year={2008}, month={Apr}, pages={588–595} }
 @article{jacobson_valdes_evans_2007, title={A numerical view into direct shear specimen size effects}, volume={30}, number={6}, journal={Geotechnical Testing Journal}, author={Jacobson, D. E. and Valdes, J. R. and Evans, T. M.}, year={2007}, pages={512–516} }
 @inproceedings{evans_frost_2007, title={Shear banding and microstructure evolution in 2D numerical experiments}, DOI={10.1061/40917(236)28}, abstractNote={A limitation of using laboratory experiments to study the micromechanics of soils is that detailed information about the specimen microstructure is typically available at only one state in a test sequence due to the destructive nature of the forensic process. To study microstructure evolution, characterization of replicate specimens tested to various global axial strain levels has been undertaken, but this procedure presents some practical and theoretical problems. Accordingly, a numerical program was undertaken using the discrete element method to model the micromechanical deformation response of particulate assemblies in two dimensions. The simulated assemblies failed via regions of high localized strain. The microstructures of these assemblies were studied as a function of global axial strain to assess evolution of local and mesoscale void ratio distributions and mean free paths. Local void ratio distributions were modeled statistically and mesoscale measurements were used to assess microstructure inside and outside of the shear bands.}, booktitle={Proceedings of GeoDenver 2007: New peaks in geotechnics}, publisher={Denver, CO: Geo-Institute of ASCE}, author={Evans, T. M. and Frost, J. D.}, year={2007} }
 @inproceedings{valdes_evans_liang_yazdanifard_2006, title={Evaluating microstructure properties of sand-rubber mixtures}, booktitle={Proceedings of the XXIII Southeastern Conference on Theoretical and Applied Mechanics: Applications of Applied Mechanics in Infrastructure, Mayaguez, Puerto Rico}, author={Valdes, J. R. and Evans, T. M. and Liang, S.-H. and Yazdanifard, R.}, year={2006} }
 @inproceedings{frost_hebeler_evans_dejong_2004, title={Interface behavior of granular soils}, ISBN={0784407223}, DOI={10.1061/40722(153)10}, abstractNote={Interface shear zones between particulate materials and continuum elements of man-made or natural materials have not been traditionally considered as shear bands. However, the results of recent micro-scale experimentation and numerical simulations have shown that they are indeed well developed partial shear bands. Further, these studies have indicated that significant similarities can be identified between these partial shear bands and what are more traditionally considered to be shear bands that evolve wholly within particulate materials. This paper presents results from physical and numerical experiments that suggest there is significant merit to this opinion. The physical experiments include quantitative analysis of the particle deformation following shear adjacent to continuum surfaces of different roughness as well as analyses of sand specimens sheared to different global strain levels. Complimentary 2-D Discrete Element Method modeling of particulate-continuum surface interfaces illustrates this parallel behavior.}, booktitle={Engineering, construction, and operations in challenging environments : Earth and Space 2004 : proceedings of the Ninth biennial ASCE Aerospace Division International Conference on Engineering, Construction, and Operations in Challenging Environments, March 7-10, 2004, League City, Houston, Texas}, publisher={Reston, VA: American Society of Civil Engineers}, author={Frost, J. D. and Hebeler, G. L. and Evans, T. M. and DeJong, J. T.}, editor={R. B. Malla and Maji, A.Editors}, year={2004}, pages={65–72} }
 @inproceedings{frost_evans_hebeler_giroud_2002, title={Influence of wear mechanisms on geosynthetic interface strengths}, ISBN={9058095231}, booktitle={Geosynthetics : state of the art, recent developments : proceedings of the seventh International Conference on Geosynthetics, 7 ICG-Nice 2002, France, 22-27 September 2002}, publisher={Lisse: Balkema}, author={Frost, J. D. and Evans, T. M. and Hebeler, G. L. and Giroud, J. P.}, editor={Ph. Delmas and Gourc, J. P.Editors}, year={2002}, pages={1325–1328} }
 @article{stormont_ray_evans_2001, title={Transmissivity of a nonwoven polypropylene geotextile under suction}, volume={24}, number={2}, journal={ASTM Geotechnical Testing Journal}, author={Stormont, J. C. and Ray, C. and Evans, T. M.}, year={2001}, pages={164–171} }
 @inproceedings{evans_meyers_gharios_hadj-hamou_kavazanjian_2000, title={The use of a capillary barrier final cover for reclamation of a closed municipal solid waste landfill}, booktitle={Proceedings of the Third Annual SWANA Arid Climate Symposium, Albuquerque, NM}, author={Evans, T. M. and Meyers, D. K. and Gharios, K. M. and Hadj-Hamou, T. and Kavazanjian, E.}, year={2000}, pages={16.1–169} }
 @article{stormont_henry_evans_1997, title={Water retention functions of four nonwoven polypropylene geotextiles}, volume={4}, ISSN={["1751-7613"]}, DOI={10.1680/gein.4.0110}, abstractNote={ The water retention functions of four nonwoven polypropylene geotextiles were measured. Each of the four geotextile types were tested in two conditions: new and cleaned. The water retention functions of each geotextile specimen were found to be hysteretic. The new geotextile specimens always contained more water at comparable suction heads than the cleaned geotextile specimens. At zero suction head, the new specimens approached saturation, whereas the cleaned specimens were less than 20% saturated. }, number={6}, journal={GEOSYNTHETICS INTERNATIONAL}, author={Stormont, JC and Henry, KS and Evans, TM}, year={1997}, pages={661–672} }