Study on soil-rock slope instability at mesoscopic scale using discrete element method

Abstract

Soil-rock mixtures (S-RM) are pervasive in nature and are heterogeneous media with continuous and discrete properties. The S-RM slope has become one of the fundamental geological environments for engineering activities due to the constant growth of engineering construction. In this study, a slope system was constructed based on the discrete element method (DEM) to analyze the micro-scale phenomena of rock-wrapping in the slope shear band and the micro-scale mechanisms, including force chains and anisotropy, under the ultimate load-bearing state. The results indicate that the slope ultimate bearing capacity increased with rock content and angularity but decreased with aspect ratio and was also affected by the spatial distribution of rocks. During the slope destabilization process, there were at least four modes of rock-wrapping movement in the shear band, and the variability of soil and rock movement caused the irregularity of shear surface in the S-RM slope. The disturbance range of slope shear dilatation was heavily influenced by rock content and angularity, and the aspect ratio was an important factor in determining the morphological characteristics of shear dilatation. The content, distribution, and shape of rocks influenced the regularity of the distribution of force chains and the anisotropy of a slope.