Fracture propagation law and slip instability induction mechanism in the structural plane of fault zone

To investigate the mechanisms of fault slip and rockburst induction, this study employs linear elastic fracture mechanics to analyze the initiation of rupture in primary fault fractures under perturbation. Formulas for displacement and stress fields of Mode I-II (tensile-shear) planar fractures are provided. Uniaxial compression acoustic emission tests on pre-fractured rock specimens reveal that crack propagation patterns closely match theoretical fracture damage expansion, elucidating the micro-scale mechanism of fault slip instability under mining influence. Macroscopically, a mechanical model for fault slip in fault zone rocks is developed. Similar material simulations and FLAC ^3D numerical modeling under mining influence identify the stress evolution and dynamic characteristics of fault slip when the working face approaches the fault. The study concludes that fault fracture development occurs within 80 m, and activation and instability initiation occur within 60 m. These findings provide theoretical and experimental support for preventing fault slip-induced rockburst disasters and developing targeted prevention measures.