Analysis of the mechanism of roof water hazards caused by fault activation

Fault activation is a common phenomenon during coal seam mining in proximity to faults. Fault activation significantly exacerbates the risk of roof water hazards through multiple mechanisms. To better understand the mechanism of roof water hazards caused by fault activation, numerical simulation and physical experiments were employed. By coupling FLAC3D with PFC3D, it is demonstrated that fault activation occurs in a phased manner, essentially involving the processes of shear failure and fracture propagation. During coal mining, fault activation causes stress concentration at fault tips and a substantial increase in the height of the water-conducting fracture zone. Furthermore, the degree of fault activation positively correlates with the advance distance; more active faults exhibit greater maximum subsidence per unit advance distance. These findings reveal that analyzing the mechanism of roof water hazards caused by fault activation provides a theoretical basis and valuable insights for preventing and controlling roof water hazards during coal mining operations near faults.