Multiphysical Geomechanics at CU Boulder

University of Colorado Boulder

Problems

Our task is to decode the mechanical and physical behaviors of geomaterials through microscale observations and upscaling. We are specifically interested in understanding the fabric and grainsize dynamics of granular materials during deformation, crushing, internal erosion and other processes. We also study the adsorption and deformation coupling of micro- and meso- porous media.

Approach

We leverage advanced theoretical and computational tools combined with experimental validations to investigate the mechanics of granular and porous materials at various time and length scales.

yida zhang multi-physical geomechanics image

Findings

We offer continuum theories that can model the co-evolution of stress, strain, grainsize and fabric of granular materials subjected to mechanical or multiphysical excitations. Based on this, numerical tools are developed for evaluating the performance of geotechnical and geological structures. Surface thermodynamics are combined with classical poromechanics to predict the adsorption-induced swelling of porous materials.

Impact

Our research aims to impact the understanding and the engineering of: (i) geotechnical structures involving granular soils subjected to long-term, high-pressure, multiphysical operation conditions (e.g., rockfill dams, tailings dams, driven piles), (ii) geological processes involving sedimentation, consolidation, cataclasis and pressure solution of minerals, (iii) drying shrinkage and adsorption swelling of natural and engineered porous materials including coal, clay and concrete.

Core competencies

Continuum thermodynamics, breakage mechanics, surface poromechanics
Discrete element simulation (DEM) and computational fluid dynamics (CFD)
High-pressure and high-temperature testing on material REVs

Current members

Xiang Zhou (Ph.D. student)
Mitul Sisodiya (Ph.D. student)
Yuxuan Wen (Ph.D. student)
Mehdi Eskandari-Ghadi (Ph.D. student)
Shubjot Singh (M.S. student)

Recent graduates

Joon Soo Park (M.S. student)
Andrew Joseph Philpott (M.S. student)
Rebecca Scheetz (M.S. student)

Funding Agencies

DOE, NNSA, ASC, industry sponsors

Additional information

1. Zheng, H., Zhang, Y., Yang, Z.X. (2019) "Suffusion-induced evolution of mechanical and microstructural properties of gap-graded soils using CFD-DEM ." Journal of Geotechnical and Geoenvironmental Engineering 146(5), 04020024, DOI: 10.1061/(ASCE)GT.1943-5606.0002245.
2. Zhang, Y., Zhou, X., Wen, Y. (2019) "A constitutive theory for sand based on the concept of critical fabric surface." Journal of Engineering Mechanics, 146(4), 04020019, DOI: 10.1061/(ASCE)EM.1943-7889.0001741.
3. Zheng, H., Zhang, Y., Yang, Z.X., (2019) "Suffusion-induced deformation and microstructural change of granular soils: a coupled CFD-DEM study." Acta Geotechnica 14(3), 795-814.
4. Zhang, Y. (2018). "Mechanics of adsorption-deformation coupling in porous media." Journal of the Mechanics and Physics of Solids, 114, 31-54.
5. Zhou, X., Ma, G., Zhang, Y. (2018). "Grain size and time effect on the deformation of rockfill dams: a case study on the Shuibuya CFRD." Géotechnique, 69(7), 606-619
6. Ma, G., Zhou, W., Zhang, Y., Wang, Q., Chang, X. (2017). "Fractal behavior and shape characteristics of fragments produced by the impact of quasi-brittle spheres." Powder Technology, 325, 498-509
7. Ma, G., Zhang, Y., Zhou, W., Ng, T.T., Wang, Q., Chen, X. (2017). "The effect of different fracture mechanisms on impact fragmentation of brittle heterogeneous solid." International Journal of Impact Engineering, 113, 132-143.
8. Zhang, Y.D., Buscarnera, G. (2017). "Breakage mechanics for granular materials in surface-reactive environments." Journal of the Mechanics and Physics of Solids , 112, 89-108.
9. Zhang, Y.D., Buscarnera, G. (2017). "A rate-dependent breakage model based on the kinetics of crack growth at the grain scale." Géotechnique , 67(11), 953-967.
10. Zhang, Y.D., Buscarnera, G., Einav, I. (2015). "Grainsize dependence of yielding in granular soils interpreted using fracture mechanics, breakage mechanics, and Weibull statistics." Géotechnique 66(2), 149-160.

Multiphysical Geomechanics at CU Boulder