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

The at-rest earth pressure coefficient, $$\hbox {K}_{0}$$K0, 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 $$\hbox {K}_{0}$$K0 and micro-scale characteristic of granular soils, beyond the macroscopic approach empirically correlated with internal friction angle. This study presents the evolution of $$\hbox {K}_{0}$$K0 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 $$\hbox {K}_{0}$$K0 during loading stage nonlinearly decreases with increasing values of friction coefficient and the assemblies with clumped particles present the lower values of $$\hbox {K}_{0}$$K0 than spherical particle assemblies of the same friction coefficient. The varying friction coefficient seems enough to capture the evolution of $$\hbox {K}_{0}$$K0 during loading, unloading and reloading cycles, while the natural sand inevitably requires the assembly with clumped particles to capture the experimentally observed $$\hbox {K}_{0}$$K0 evolutions.