Dynamic modelling of soil-rock-mixture slopes using the coupled DDA-SPH method

Abstract

Soil-rock-mixture (SRM) slopes widely exist, and their failure may cause serious damage to infrastructures and endanger human lives. Thus, it is important to study the mechanical behaviors of SRM slopes. Analyzing these behaviors is complicated and typically involves soil-rock-structure interactions. Fortunately, numerical methods can provide adequate descriptions of these behaviors. Discontinuous deformation analysis (DDA) is a powerful method that can be used to simulate the behavior of solid blocks, including rocks and structures. Smoothed particle hydrodynamics (SPH) can effectively simulate the behavior of fluid flows and soil materials. To take advantage of both methods, the coupling of DDA and SPH is investigated in this study, where the coupled DDA-SPH method is used to study the mechanical behaviors of SRM slopes. Two verification tests are investigated to demonstrate the accurate calculation of the interaction force and impact force using the coupled method. A series of simulations are then performed considering different shapes, sizes and contents of rocks and their distributions in SRM slopes. Results show that the deformation of the SRM slope is proportional to the roundness but inversely proportional to the sorting coefficient of the rock blocks. Additionally, the deformation of the SRM slope with rocks distributed along the potential sliding surface is much smaller than that with rocks distributed in the sliding body. In addition, the runout distance of an SRM landslide and the maximum impact force on nearby buildings increase with higher rock contents, which is more destructive to nearby structures and human lives.