A Numerical Analysis of Coal Burst Potential After the Release of the Fault-Slip Energy

Fault-slip instability due to mining is a critical factor leading to coal bursts. To better understand the impact of fault-slip release energy on a coal seam, a static and dynamic numerical calculation model was established using FLAC3D with geological conditions at a mine longwall face in contact with the fault. The change in coal seam parameters under a dynamic fault-slip load was studied, including the change in vibration velocity, displacement, abutment stress, and strain energy density. The coal seam impact hazard level was classified with the change in longwall‒fault distance. Meanwhile, the numerical simulation results were compared and analyzed with microseismic monitoring records at the mining site to verify the accuracy of the results. The results showed that the increase in vibration velocity and displacement under the dynamic fault-slip load, and the sudden increase in abutment stress and strain energy density are precursors for coal bursts. As the longwall‒fault distance decrease, the coal seam is in a high-stress state, and the internal strain energy accumulates. After the dynamic fault-slip load is transferred to the coal seam, the high static and strong dynamic loads are superimposed, leading to an increased risk of coal bursts. Additionally, the coal seam stability was analyzed under three influencing factors, including the seismic energy, the seismic source location, and the burial depth. This study contributes to a better understanding of the mechanism for dynamic fault-slip loading on coal seam disturbance and provides insight into the associated coal burst propensity assessment.