近距离重复采动煤层底板破坏深度微震监测研究及应用

Failure Depth of Coal Seam Floor Is Repeatedly Mined at Close Range Research on Microseismic Monitoring and its Engineering Application

带压采面底板突水事故是矿井常见的生产事故之一,预防底板突水有效方法是进行底板破坏深度探测。针对平煤股份十矿近距离重复采动煤层存在隔水层被二次破坏、底板破坏深度叠加、底板易涌水突水等实际问题,通过采用矿井微震动态监测和理论计算两种方法,对重复采动煤层底板破坏深度进行对比分析,绘出非常接近正态分布的微震事件底板破坏深度区间分布图,得出了精确的底板破坏深度发育范围,为提高煤矿水害预测能力和安全管理水平奠定了基础。研究表明:微震事件优势发育时间段为08:00-15:00的检修班期间内,主要集中在采线前方150 m范围内,顶板微震事件发育最高到己17煤层顶板96.67 m,底板微震事件发育最深到己17煤层底板84.78 m,取置信度为95%情况下确定工作面底板破坏深度的发育下限为40 m,且破坏深度处于理论分析范围内(35.02~42.96 m),验证了微震动态监测应用于探测底板破坏深度的准确性。

Floor water inrush with pressure mining face is one of the common production accidents in mine.The effective way to prevent floor water inrush is to detect floor failure depth.In view of the practical problems such as secondary failure of water-barrier layer,superposition of floor failure depth,and easy water inburst of floor in Pingmian Joint Stock No.10 mine,the failure depth of floor of repeated mining coal seam is compared and analyzed by using two methods of mine microseismic dynamic monitoring and theoretical calculation,and the interval distribution diagram of floor failure depth of microseismic events that are very close to normal distribution is drawn.The accurate development range of floor failure depth is obtained,which lays a foundation for improving the prediction ability and safety management level of coal mine water damage.The results show that the dominant development period of microseismic events is 08:00-15:During the maintenance shift of 00,the microseismic events were mainly concentrated in the 150 range in front of the mining line.The maximum development of roof microseismic events was 96.67m in the roof of H17 coal seam,and the deepest development of floor microseismic events was 84.78m in the floor of H17 coal seam.If the confidence degree was 95%,the lower limit of development of failure depth of working face floor was determined to be 40m.The failure depth is within the theoretical analysis rang(35.02~42.96m),which verifies the accuracy of microseismic dynamic monitoring applied to detect the failure depth of the floor.