Study on instability fracture and simulation of surrounding rock induced by fault activation under mining influence

The fault is potentially vulnerability's geological structure in the working face and its vicinity, and it is also a crucial geological factor affecting coal mine safety exploitation. To investigate the unstable failure of surrounding rock induced by fault activation under the influence of adoption, which was studied utilizing field case and numerical analysis for the deformation and failure process of surrounding rock near the fault-affected zone. Combined with field cases, this paper analyzes disturbance stress and roof abscission layer monitoring in effecting zones of fault activation. Using the discrete element 3DEC numerical analysis method, the model of surrounding rock unstable fracture induced by fault activation under adoption is established. The unstable fracture and stress variation characteristics of surrounding rock induced by fault activation during the excavation of the upper side wall and lower side wall of the faults are simulated and analyzed. Field analysis shows that as the coal working face continues to advance, the mining stress gradually increases. There is a zigzag wave on the relationship curve between coal mining and roof displacement near the fault, which reveals that the surrounding rock of the fault activation affected zone is in the superposition state of static load and dynamic load. Furthermore, the simulation results show that the stress and displacement of surrounding rock near the fault increase with the advance of coal mining face. The closer to the fault plane, the displacement gradually returns to zero, and the stress is also in a lower state.