A Study on the Variation Characteristics of Floor Fault Activation Induced by Mining

Coal seam floor water inrush is one of the most significant hazards affecting the safety of coal mine operations. To prevent water inrush incidents, it is critical to investigate the evolution of fault characteristics during the mining of working faces. This study takes the 4104 working face of the Heshan mine in China as the engineering case, and a fluid–solid–damage coupling numerical model of the mining process is established. COMSOL multiphysics software is employed to analyze the evolution of fault characteristics in the coal seam floor under mining-induced disturbances. The results show that under mining disturbances, the stress on the fault plane decreases initially and then increases, with higher stress at the sides and lower stress in the center. These stress variations induce alternating states of sliding and stability on the fault plane, indicating that fault reactivation manifests as a dynamic, non-equilibrium process. As the rock mass gradually deteriorates, the stress field at the fault zone undergoes redistribution, leading to fault reactivation. This process further exacerbates damage to the rock mass, resulting in a continuous increase in the permeability coefficient within the fault zone, thereby elevating the probability of water inrush hazards. Areas with more severe damage typically exhibit higher permeability, forming high-risk zones for water inrush. This study explores the characteristics of fault reactivation and its relationship with the seepage field, providing a theoretical basis for coal mining enterprises to prevent and control fault-induced water inrush.