Coupled effects of particle shape and inter-particle friction on quasi-static shear behavior of dry granular materials studied by 2D LS-DEM

Abstract

We perform a series of quasi-static simple shear tests on samples of superdisks using the level set discrete element method (LS-DEM). We then define the shapeinduced clusters as the mesoscopic structure, and relate its characteristics to the critical-state macroscopic properties and microscopic contact anisotropy. We find the following. (1) The shear strength increases as the particle blockiness b_k increases, except when the inter-particle friction μ_p is low. In contrast, the mean solid fraction always reaches the peak value at around b_k = 5. (2) The cluster size distributions collapse onto a single power-law decay curve previously fitted for elliptic packings, although the tails gradually deviate as μ_p increases. (3) The differences in shear strength and mean solid fraction are mainly attributed to the clusters.