Abstract:
Aiming at the frequent occurrence of strong mine pressure disasters during the mining of deep gently inclined extra-thick coal seams, we take the 130207 working face in the Ningdong Lingwu mining area as the engineering background. The FLAC
3D numerical simulation method is adopted to establish a refined three-dimensional model, and the strong mine pressure behavior law of the working face is studied. The results demonstrate that: The mechanism of strong mine pressure behavior is dominated by stress concentration: as the working face advances, vertical stress transfers significantly to coal pillars and ribs and accumulates nonlinearly. When the face advances to 400 m, the maximum vertical stress of the roof reaches 32.5 MPa, and the stress concentration factor increases to 2.61, constituting the core inducement of strong mine pressure behavior. The evolution of the plastic zone reveals the catastrophic path: unloading on the gob-side triggers a bidirectional expansion of the overburden plastic zone towards the goaf (with a maximum height of 5 m), and the failure mode transforms from shear to tension. This forms the direct spatial carrier and the key disaster-prone area for overburden instability and collapse under strong mine pressure. The dynamic process of overburden fracturing: when the face advances to 200 m, main roof fracture leads to the connection of high-level bed separations, and stress transfer to coal pillars induces tensile failure. After advancing to 300~400 m, the bed separations become compacted and tend to stabilize, while stress concentration continues to intensify. Through dynamic simulation, this study reveals the stress-failure coupling mechanism of strong ground pressure in deep gently inclined extra-thick coal seams, providing a theoretical basis and engineering reference for optimizing support design and preventing rock burst.