Dynamic Analysis of the Rock Burst Potential of a Longwall Panel Intersecting with a Fault

摘要

Faults are one of the most common geological structures in underground mining. Affected by mining activities, fault-slip events will release large amounts of energy and trigger seismic waves, which could induce rock burst events and endanger mining operations. In this study, a longwall panel intersecting with a fault is introduced, as well as field microseismic (MS) monitoring. Static and dynamic numerical analyses are conducted to investigate the fault parameters' effects on the behaviors of the fault. The results show that the friction angle (phi(f)) significantly affects the shear displacement, magnitude and distribution of the seismic moment; the fault stiffness has a great effect on the magnitude of the seismic moment but smaller effects on the shear displacement and the distribution of the seismic moments. Based on the influence of the fault stiffness and phi(f) on the seismic moment, reasonable fault parameters can be determined. By employing the calibrated parameters, the dynamic responses and the rock burst potential of the surrounding rocks were analyzed by means of the peak particle velocity (PPV) and stress distribution. The propagation of the seismic waves released by fault-slip events excites the particle velocity of the rock mass, and there is a strong correlation between the particle velocity and rock mass damage. As the working face advances toward the fault, the PPV and stress fluctuation of the peak abutment stress rise significantly, which result in a great increase in the rock burst potential. The rock burst potential changes with the mining activities; therefore, corresponding measures must be applied to prevent and control rock burst events. This study contributes to deepening our understanding of the fault parameters in numerical simulations and the dynamic responses and rock burst potential of the surrounding rocks due to mining activities and provides a back-analysis calibration method for the fault parameters.