Experiments on the characteristics of thrust fault activation influenced by mining operation

With the background of F16 large thrust fault in Yima mining area, a similar model was built based on the geological drilling data and underground exposed structure from five coal mines influenced by the fault. Considering the fractal characteristics and occurrence of overburden on both sides of fault surface, the overburden movement, mine pressure behavior law and dynamic response before and after fault activation were studied by monitoring acoustic emission (AE), overlying strata displacement and stress in mining area. The results demonstrate that the overburden movement, mine pressure and dynamic response show a great difference before and after fault activation influenced by the complicated overburden occurrence structure and the tectonic movement. Before fault activation, the "three zone" of overburden is obvious, and the floor stress is hardly affected by mining and the AE signal is weak. In the fault influential area, the roof abscission layer increases immensely, the fault activation is triggered by mining stress, the floor stress reached the maximum, and the total number of AE events and energy release rate grows abruptly. After crossing a certain distance from the fault, the buckling failure of mining face and the floor stress increase with the increasing length of cantilever rock beam. When bearing stress is released by the caving of antilever rock beam, the floor stress decreases, and the "short block voussoir beam" above the workface cuts down and slides along the fault plane with enormous AE events. © 2016, China University of Mining and Technology. All right reserved.