Response mechanism characteristics of mining-induced fault activation

In the process of coal mining, mining-induced stress perturbation is a key factor leading to fault activation, which is a primary challenge faced by safe coal mining. Fault activation is prone to induce geological disasters such as rock bursts and floor water inrushes of coal mines. Furthermore, it poses a serious threat to mining safety. Using the Flac^3D software for numerical simulations and similar material simulation experiments, this study established a model for faults’ stress-displacement responses under coal mining to analyze the mechanisms behind the evolution of fault structure zones in the process of coal mining. Key findings are as follows: (1) During coal mining, disturbance produced an impact earlier on stress than on displacement, and the stress peaked. (2) When the stress peaked, reaching the yield limit, the disturbance began to gradually induce displacements. (3) As the mining face constantly advanced, coal mining induced the large-scale collapse of overburden rock layers, which interpenetrated the fault zone, progressively inducing the activation of the fault zone. (4) Rather than a one-time full-stage activation, the coal mining-induced fault activation progressed gradually from upper to lower parts, exhibiting significant spatial and phased characteristics. This study, ascertaining the occurrence characteristics of fault activation, can effectively improve the early warning and prevention of a series of geological disasters and accidents, such as rock bursts and floor water inrushes, indirectly caused by fault activation. Therefore, this study holds great significance for the safe and efficient mining and production of coal mines.