Mechanical behaviour of granular media in flexible boundary plane strain conditions: experiment and level-set discrete element modelling

This article presents the results of level-set (LS) discrete element method (DEM) simulations with experimental comparisons of flexible boundary plane strain tests in granular media. The grain-scale micromechanics at the particle level is captured well with LS-DEM, while the overall macroscopic response of the specimen is in quite good agreement with the simulation results. Onset and evolution of localized zones of shear strain accompanied by a significant amount of grain rotation could be well apprehended in the simulations, while the bulging of the specimen could be noticed in the experimental findings as well as in the model predictions. Multiple zones of shear strain accumulation in conjugate arrays were also observed on subsequent biaxial shearing of the sand specimen. The computational results furnish a quantitative estimate of the evolution of force chains and grain fabric orientation. Initially, these force chains were isotropic which on further deformation oriented in the direction of loading, and the grains aligned themselves in their preferred fabric orientation and remained in that fashion till the end of biaxial loading.