孤岛工作面冲击地压多指标监测及危险性区域划分

孤岛工作面回采过程中受煤柱应力集中和工作面动压的叠加影响,容易发生冲击地压灾害。现有方法采用单一指标对冲击危险性进行预警,存在较大的预警误差,无法全面反映采掘过程中的冲击危险性。针对上述问题,为了研究孤岛工作面回采过程中的冲击地压危险程度,以济宁二号煤矿93下05孤岛工作面为工程背景,提出了孤岛工作面冲击地压多指标监测方法,利用工作面回采过程中钻屑量、微震、钻孔应力等多指标综合分析了该工作面的冲击危险性,并根据工作面不同区域的冲击地压危险性进行了区域划分。分析结果表明:在联络巷附近及未保护区,微震日最大震动能量及震动总能量、钻屑量及钻孔应力值均明显提高,得出在孤岛工作面回采过程中,联络巷附近及未保护区是冲击地压的危险性区域。根据危险性区域划分结果,考虑到在不同区域应力集中程度的差异性,提出并提前实施了参数差异化的大直径卸压防冲措施,降低了应力集中程度,防止了冲击地压灾害发生。

Multi-index monitoring of rock burst and risk zone division of island mining coal face

Under superposition influence of stress concentration of coal pillar and dynamic pressure of working face in mining process of island mining coal face,rock burst disaster is easy to occur.At present,the single index is used to give early warning to the impact risk,which has large error in early warning and cannot fully reflect impact risk in the mining process.For the above problems,in order to study hazard degree of rock burst in the mining process of island mining coal face,taking 93 down 05 island mining coal face of Jining No.2 Coal Mine as engineering background,a multi-index monitoring method of rock burst of island mining coal face was put forward.The impact risk of the working face was analyzed by means of cuttings,microseismic and borehole stress,and risk zones were divided according to the impact risk of different areas of the working face.The analysis results show that the maximum and total vibration energy of microseismic day,cuttings and borehole stress value are significantly increased in the vicinity of connection roadway and unprotected area,and it is concluded that the vicinity of connection roadway and unprotected area are the dangerous areas of rock burst during the mining process of the island mining coal face.According to the result of the classification of dangerous regions and considering the difference of stress concentration degree in different regions,a large-diameter pressure relief and anti-impact measure with parameter differences was proposed and implemented,which reduces the stress concentration degree,avoids the energy accumulation and prevents occurrence of rock burst disater.