Deformation and failure of fractured surrounding rock in roadway under dynamic loading: numerical simulation based on FDM-DFN coupling

This study investigates the deformation and failure patterns of fractured surrounding rock in roadways under dynamic loading. A finite difference method (FDM) and discrete fracture network (DFN) coupling model was constructed using FLAC^3D numerical simulation software to analyze the deformation and failure characteristics of surrounding rock under varying peak particle velocity (PPV). Results show that: ① Compared with the Mohr-Coulomb model, the FDM-DFN coupling model could better reflect the heterogeneity characteristics of rock mass, better characterize the deterioration effect of cracks on surrounding rock, and perform more reasonable simulation on the fractured surrounding rock in roadway. ② As the PPV increased, stress concentration zones shifted towards deeper regions, leading to significant deformation of the surrounding rock in roadway. The plastic zone was dominated by shear failure and extended to the deep part of the rock layer. ③ Both the deformation magnitude of the surrounding rock and the volume of the plastic failure zone exhibited a positive correlation with PPV, while the maximum vertical stress and the maximum horizontal stress in the surrounding rock followed a cubic polynomial relationship with PPV. This study provides evidence for stability analysis of fractured surrounding rock in roadway.