上覆遗留煤柱作用下冲击矿压预测预警案例研究

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

以三河尖煤矿92201工作面运输巷在上覆7煤上山保护煤柱下掘进诱发的冲击矿压为例,采用震动波CT技术对待掘区域应力场进行反演,预测冲击危险区域,并在掘进过程中实时监测分析矿震动载特征,对冲击危险进行预警。研究表明:震动波CT技术可有效反应煤岩体内未知因素对应力分布的影响,实现大范围应力探测,较常规解析和数值等分析方法更为有效,利用该技术可提前和分时段预测冲击危险区域分布;结合掘进过程中的矿震时空演化规律分析,可对冲击危险区域进行有效确认和实时预警,实现了动载与静载结合对冲击危险进行提前预测与实时监测预警。利用该套技术方法分析表明,上覆遗留煤柱长时间受矿压作用,其集中应力分布明显向煤柱煤壁深处转移,导致区域应力分布异常,冲击矿压防治难度加大。92201巷道冲击矿压显现证实了以上结论和该套技术方法的有效性。

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. © 2016, Editorial Office of Journal of China Coal Society. All right reserved.