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Abstract Forewarning of rock burst induced by shock bump is a worldwide problem. Long-term spot monitoring and study on the mechanism of monitoring and forewarning shows that the sudden decrease of stress in the stope monitoring area is a precursor to this kind of rock burst. We can obtain the mechanism of spot forewaring based on the stress drop in coal and rock mass before shock bump occurred by analyzing the inner relationship between fracture characteristics of the key stratum triggering shock bump and variation laws of stress in coal and rock mass. The mechanism is that advanced abutment pressure evolves from single peak to double peaks before and after the tensile fracture of the overlying key stratum，and stress drop occurs in the coal and rock mass beneath the fracture position of the key stratum. After that about a few minutes，the strong dynamic load induced by rock beam rotation and fracture leads to rock mass destruction and shock bump in the below loading area. According to the drop value of spot stress and its variation range，the damage extent and influence scope of shock bump can be determined，and thus spot control measures can be adopted timely. Combined with predicting breaking span of the key stratum before mining，tracking rock fracture height by high-precision microseismic monitoring technology can estimate the danger area where shock bump will happen. This whole prediction method will enhance the time-effectiveness and accuracy of spot forecast. The phenomena and critical data revealed in this paper provide a direct and effective approach to the spot forewarning for rock burst induced by shock bump.
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2015, Vol. 34 
