Dem investigation of volumetric loss-induced failure mechanisms and soil arching evolution in inherent anisotropic sandy soil strata

Abstract

Soil arching effect induced by volumetric loss frequently leads to stress redistribution of sandy soil, even resulting in surface subsidence hazards. To systematically investigate the formation and evolution mechanisms of soil arches in inherent anisotropy strata, this paper conducts a set of anisotropic granular packing prepared for trapdoor tests with the objective of examining the effect of bedding angles ($\alpha$) in sandy soil on the arching effect by employing the Discrete Element Method (DEM). This investigation systematically presents outcomes encompassing load–displacement curves, arching deformation patterns, and ground response within formations featuring distinct $\alpha$. Furthermore, microscopic analyses are further adopted to endeavor to elucidate the behaviors influenced by $\alpha$. Results indicate that under low fill heights, the specimen with$\alpha$ = 0° inclination exhibits a higher minimum load compared to others, attributed to increased bending moments generated by contact forces within the shear band. Specimens with$\alpha$ = 30° and 60° inclinations demonstrate significant lateral shifts in their maximum surface settlement points, a behavior accurately captured by the modified Peck formula proposed in this study. Furthermore, a three-stage evolution curve of soil arching is introduced to characterize the failure modes of granular materials.