Numerical Simulation of the Influence of Skeleton Particle Roughness on the Mechanical Behavior of Cemented Soil‐Rock Mixtures Under Cyclic Loading

The roughness of skeleton particles is a critical factor influencing the macroscopic mechanical properties of cemented soil‐rock mixtures (CSRM). Under cyclic loading, the quantitative effect of roughness on macroscopic material performance is challenging to ascertain. This study employed spherical harmonic reconstruction to generate particle models that consider realistic surface morphology. Three‐dimensional discrete element method (DEM) numerical specimens reflecting different roughness levels were established. Through cyclic shear numerical tests under varying roughness conditions, the influence of roughness on the macroscopic hysteresis characteristics and stress‐strain response of the material was quantitatively analyzed. Furthermore, the underlying mechanism was elucidated by examining mesoscopic features, including displacement fields, and the magnitude and spatial distribution of contact forces. The results indicate that as roughness increases, the connectivity of the force chain network is enhanced, and the constraining effect of skeleton particles on the displacement of surrounding soil is improved, effectively suppressing interparticle sliding and rotation. Macroscopically, this manifests as a reduction in hysteresis loop area and an enhanced deformation resistance under cyclic loading. Additionally, increasing the loading rate further strengthens the peak deviatoric strength of the material and inhibits crack propagation. The findings provide a reference for evaluating the mechanical performance of CSRM under cyclic loading.