Numerical Investigation of Particle Shape Effect on Sand Shear Strength

Abstract

The particle shape contributes significantly to sand mechanical properties but is difficult to study in laboratory experiments. In this study, microscopy experiments were used to classify sand particle morphologies as spherical, non-spherical and ball-shaped. Particles with these three morphologies were modeled using the discrete element method to analyze the effect of the particle shape on the shear strength in a direct shear test simulation. The simulation results showed that the non-spherical particles and balls exhibited the highest and lowest peak shear strengths, respectively, under a low vertical stress. The highest and lowest contact force numbers were observed for the non-spherical particles and balls, respectively. The sand particles exhibited a higher resistance to motion with increasing contact force numbers, resulting in a higher shear strength. For particles with low sphericity (S) and roundness (R) values, a high number of contacts and interlocking structures can form, increasing resistance to external forces. As the S decreased, the anisotropy in the contact force increased during the test, and the contact number distribution of the spherical particles tended to remain isotropic during the entire process.