Numerical investigation of the at-rest earth pressure coefficient of granular materials

Abstract

The at-rest earth pressure coefficient, , is one of the most fundamental values for evaluating in-situ soil stresses and designing foundation. Research has been expanded to investigate the correlation between and micro-scale characteristic of granular soils, beyond the macroscopic approach empirically correlated with internal friction angle. This study presents the evolution of values of irregularly shaped natural sand, spherical shaped smooth and rough surfaced glass beads along with the stress history, estimated by the discrete element method. The surface roughness and non-spherical particles were emulated by inter-particle friction coefficient and the clumped particles. Results exhibit that the during loading stage nonlinearly decreases with increasing values of friction coefficient and the assemblies with clumped particles present the lower values of than spherical particle assemblies of the same friction coefficient. The varying friction coefficient seems enough to capture the evolution of during loading, unloading and reloading cycles, while the natural sand inevitably requires the assembly with clumped particles to capture the experimentally observed evolutions.