东滩矿弱化低位关键层治理矿震技术研究

Mine earthquake control through weakening the low key stratum in Dongtan Coal Mine

针对坚硬顶板造成的矿震动力灾害问题,通过理论研究、数据分析等方法分析了东滩煤矿矿震发育特征。依据关键层理论,结合微震探测,确定了关键层位置,探讨了矿震防治技术原理,提出了煤矿井下分段水力压裂弱化减震技术,并开展了工程示范应用。结果表明:矿震灾害发生具有周期性,与周期来压呈现协同发生规律特征;矿震致灾能力阈值为5×10^(3)J,致灾矿震多集中发生在距离煤层顶板15.13m的中粒砂岩亚关键层。对该层位进行分段水力压裂弱化治理后,致灾矿震事件日平均发生次数下降了95.45%,常规矿震(能量小于5×10^(3)J)事件的日平均发生次数提高了80.5%。该技术促使关键岩层能量分散释放、均布化,降低了单次矿震能量,安全掩护了工作面回采。

In view of the dynamic disaster of mine earthquake caused by hard roof,the development characteristics of mine earthquake in Dongtan Coal Mine are analyzed by theoretical research and data analysis. Based on the key strata theory,combining with microseismic detection,the location of the key strata is determined,the technical principle of mine earthquake prevention and control is discussed,and the technology of segmented hydraulic fracturing weakening and shock absorption in underground coal mine is proposed and applied in an engineering demonstration project. The results show that: the mine earthquake occurs periodically,and synergistically with the periodic weighting;the disaster-causing threshold of mine earthquake is 5 × 10^(3) J,and the disaster-causing mine earthquake mainly occurs in the sub key strata,a medium grained sandstone 15. 13 m away from the coal seam roof. After the segmented hydraulic fracturing weakening,the average daily number of disaster-causing mine earthquake events decreases by 95. 45%,and the average daily number of conventional mine earthquake events( energy less than 5 × 10^(3) J) increases by 80. 5%. The technology can promote the energy dispersion and distribution of key strata,thus to reduce the energy of single mine earthquake,and protect the mining face.