急倾斜特厚煤层水平分段开采诱冲机理及防治技术

Rock burst induced by horizontal sublevel mining in a steeply-inclined and extra-thick coal seam and its prevention technology

为了研究急倾斜特厚煤层水平分段开采期间工作面冲击地压机理,以窑街三号井LW5521-20工作面工程地质条件为背景,通过现场调研、理论分析、工业性试验、SOS微震监测和钻屑量监测等手段,对LW5521-20工作面开采诱冲机理及防治技术进行了研究。结果表明:急倾斜煤层水平分段开采期间顶板和底板附近的侧面支承应力沿Ox轴呈非对称分布;当覆岩中悬顶破断引起的动载荷和煤体承受的高集中静载荷叠加作用超过冲击临界载荷时,就会发生冲击地压;当工作面附近煤体引起的附加动载荷与液压支架上的初始静载荷叠加作用超过其自身承载能力时,液压支架发生损坏;采用深孔预裂爆破、煤体卸压爆破以及工作面支护优化等措施,可有效防治冲击地压。

In order to study the mechanism of rock burst in working face during horizontal sublevel mining in steeply-inclined and extra-thick coal seam,the engineering geological conditions of LW5521-20 working face of Yaojie No.3 shaft is taken as the background,through on-site investigation,theoretical analysis,industrial test,SOS microseismic monitoring and drilling cutting weight monitoring,etc.,the mechanism of rock burst induced by LW5521-20 working face mining,and the control technology is studied.The results show that the lateral supporting stresses near the roof and floor are asymmetrically distributed along the Ox axis during the horizontal sublevel mining of the steeply-inclined seam;when the dynamic load caused by overhanging roof breakage in overburden rock and the superimposition of high concentrated static load on coal body exceed the critical impact load,rock burst will occur;when the superimposition of the additional dynamic load in the coal body near the working face and the initial static load on the hydraulic support exceeds the support’s carrying capacity,the hydraulic support will be damaged.The rock burst can be prevented by adopting deep hole pre-splitting blasting,coal pressure relief blasting and optimizing of the working face support.