Modeling the direct shear test using the Discrete Element Method

In the present article, a direct shear test was modeled using the Discrete Element Method. This approach describes the soil as an assembly of particles, reproducing the macroscopic soil behavior from micro-mechanics interactions between individual particles (Cundall 2001). About 70,000 particles were used in a DEM model, developed to reproduce a direct shear test. The sizes of the particles were consistent with the real granulometry. Several methodologies were conducted in order to reproduce an initial void ratio similar to those obtained experimentally. The numerical model results will be compared with experimental tests of a coarse sand from previous stages of this research (Pardo & Saez 2014, Pardo 2013). The goal is to accurately reproduce the macro-scale response of the laboratory tests with the DEM model, and to study the effect of the micro-parameters in the stress path and the deformation of the material. The results show that, including a rolling resistant model, the stress response can be appropriately reproduced with this method, but the the dilatancy characteristics of the sand was very difficult to replicate.