Case study on prediction and warning of rock burst under overlying pillar

Taking the rock burst in No.92201 roadway under overlying uphill protecting coal pillar of No.7 coal seam at Sanhejian coal mine as the example, the inversion of stress field in awaiting excavation area was carried out to predict rock burst hazard using seismic computed tomography technique.Real-time monitoring and analysis of mine tremor dynamic load characteristics were used for rock burst warning during the process of roadway excavation.The results indicate that the large range of stress can be detected by seismic computed tomography technique responding the influence of unknown factors in coal and rock mass to stress distribution, which is more effective than the conventional analysis and numerical analysis method, therefore it can be used to predict the regional distribution of rock burst hazard in advance and at different time periods.Combining with the analysis of the temporal and spatial evolution of mine tremor in tunneling process, the rock burst hazard area can be effectively confirmed and a real-time warning is achieved, which means that the combination of dynamic load and static load is useful to forecast the rock burst hazard area.The analysis of technical method using this technology shows that the stress concentration in pillar transfers obviously to the deep coal mass due to long time ground pressure, resulting in the abnormal distribution of regional stress and a more difficult prevention of rock burst.The rock burst in No.92201 roadway confirms the accuracy of above conclusions and the validity of the technology.