急倾斜特厚煤层水平分段开采冲击机理及防治

Mechanism and prevention of rock burst induced by horizontal sublevel mining of a steeply inclined extra-thick coal seam

为了防治急倾斜特厚煤层水平分段开采冲击地压灾害,以甘肃窑街三矿为工程背景,提出了急倾斜特厚煤层工作面冲击地压的动静载叠加诱发机理以及针对性的防治对策。结果表明:由采动应力非对称分布引起的夹持煤体高集中应力是急倾斜煤层冲击的静载力源,而覆岩破断及结构失稳所形成的强动载是冲击的主要动载力源;在动静载叠加作用下,当应力达到急倾斜煤岩大范围失稳临近载荷则诱发冲击灾害。基于急倾斜煤层开采诱发冲击的动静载力源特征,建立了综合采用顶板深孔预裂爆破控动载、巷帮与底煤爆破或大直径钻孔卸静载的三位一体冲击地压防治技术体系,并成功应用于窑街三矿五采区工作面。

In order to prevent the rock burst caused by horizontal sublevel mining of a steeply inclined extra-thick coal seam,the mechanism of rock burst induced by the superposition of dynamic and static loads and the corresponding prevention measures were proposed.Taking Yaojie No.3 coalmine in Gansu Province as the engineering background,the results show that the high concentrated stress caused by the asymmetric distribution of mining stress is the source of static load for rock burst,while the strong dynamic stress caused by the overburden fracture and structural instability is the main source of dynamic load for rock burst.When the total stress reaches the critical stress of large-scale instability of coal-rock mass,the rock burst will occur.Based on the characteristics of dynamic and static load sources,a trinity rock burst prevention and control technology system was established,which comprehensively adopted the deep-hole pre-split blasting in roof for controlling dynamic load,blasting of roadway side and bottom coal or unloading static load by large diameter borehole.The above prevention measures have been successfully applied to the working faces in No.5 mining district of Yaojie No.3 coal mine.