The occurrence mechanism and influencing factors of fault-slip rockburst

No method can simulate the stress wave generated by fault slip in the previous numerical simulation of fault-slip rock-burst. As a result, the radiation characteristics cannot be simulated realistically, which causes the unclear mechanism of fault-slip rock-burst. Therefore, the mechanical-parameter steepest descent method and static-dynamic analysis method were proposed. Taking the 7301 working faces of Zhaolou Coal Mine as the engineering background, the work analyzed the radiation characteristics of slip stress waves and the evolution characteristics of stress, cracks, and energy in the surrounding rocks of roadway in the process of rockburst. Besides, the influence law of fault geometric properties on rockburst was studied. (1) The mechanical-parameter steepest descent method based on the Mohr-Coulomb criterion could realistically simulate the stress waves generated by fault slip. (2) The fault-slip stress waves had the radiation characteristics of the P and S waves. The vibration velocity around the source was anisotropic, and the velocities of the P and S waves were 1,449 and 833 m/s, respectively. The simulation results were similar to real data. (3) The whole process of rockburst induced by fault slip was simulated. The process of fault-slip rockburst existed at the stable stage, initial rockburst stage, and full-scale rockburst stage. The number of tension cracks during the calm period was used as precursor information for rock-burst. (4) The geometric characteristics of faults determined the radiation intensity and radiation area of the fault-slip stress waves, which significantly affected rockburst. The rockburst risk was higher in the roadway in the main radiation area of the S wave. Mechanical-parameter steepest descent, a numerical simulation method, provides a reference for simulating stress waves generated by fault slip. The results provide a basis for understanding the occurrence mechanism of fault slip rockburst and predicting the fault slip rockburst in real engineering.