Abstract: The direct shear behavior of soil is important to the design of the mining and the agroforestry machinery. In this study, the Discrete Element Method (DEM) is adopted for the numerical investigation of the direct shear test on the sandy silt soils. The soil particles are represented by spheres of different sizes; the interaction between particles is simulated with the linear contact model; and the parallel bond model (PMB) is used to simulate adhesive interaction. To calibrate and validate the numerical model and the parameters used in this study, the shear strength values under different vertical load varying from 100kPa to 400kPa with those of the standard soil direct shear tests were compared. It is found that the DEM numerical results and the experimental results are in a good agreement. In addition, the particle movement during the shearing process was also studies; the influences of the shearing box shape, shearing velocity and normal load to the shearing curve and porosity of particle bed are also discussed in detail in the paper.

Key words: Sandy Silt Soils, Direct Shear Test, Discrete Element Method, Numerical Simulation