厚煤层邻空巷道动力冲击机理及控制技术

Mechanism and control technology of dynamic impact in near goaf roadway with thick coal seam

针对大同矿区厚煤层坚硬顶板条件下,综放工作面邻空巷道超前支护段矿压显现强烈,并间歇性出现动力冲击现象问题,以同忻煤矿8202工作面5202巷道为研究对象,采用理论分析与现场实测相结合的方法,对邻空巷道动力冲击发生机理进行研究。研究结果表明:厚煤层坚硬顶板条件下,8203工作面采空区边界上覆各岩层形成倒台阶组合悬臂梁结构,在双向叠加支承压力作用下,高位悬臂梁的破断失稳是造成邻空巷道5202巷动力冲击现象的根本原因,基于此利用定向高压水力致裂技术,对区段煤柱上覆的1号、2号亚关键层提前预裂,使高应力沿8202工作面推进方向发生转移。微震监测结果表明,水力致裂后5202巷道超前支护段动力冲击现象显著减弱,取得了良好的效果。

Aiming at the problems of the strong strata behaviours and intermittent dynamic impact phenomenon in Datong Minefield with hard roof and thick coal seam,taking the No.5202 roadway in Tongxin Coal Mine as an example, combined with theoretical analysis and field measurement, the mechanism of dynamic shock in adjacent roadways was studied. Results showed that in the hard roof condition of thick coal seam, the goaf of Workface 8203 formed invert-step composite cantilever structure.Under the action of biaxial superimposed sup- port pressure, the fracture of high cantilever is the basic reason of dynamic shock in adjacent roadways. Based on this point, an effective control technology with the orientated high-pressure hydraulic fracturing of roadway roof was proposed and applied to the No. 1 inferior key strata and No.2 inferior key strata.The application of technology achieved the high stress transfer into the Workface 8203.The microseismic monitoring results showed that the dynamic impact phenomenon in Roadway 5202 decreased obviously, and achieved good effects.