厚硬顶板冲击地压发生机理及防治实践

Mechanism and prevention practice of rock burst in thick and hard roof

基于鄂尔多斯地区冲击地压矿井厚硬顶板加坚硬煤层的特征,对宽煤柱开采条件下冲击地压发生过程进行分析,揭示了该区域冲击地压是由厚硬顶板破断引起煤体高应力区动力系统失稳产生震动、激发应力波,应力波与塑性区煤体相互作用而产生的;以巴彦高勒煤矿为例,采用深孔爆破对巷道顶板进行卸压。结果表明:在未断顶区域,顶板发生极限破断引发大能量微震事件,能量释放集中在沿空巷侧,现场存在动压显现现象;在正常断顶区域,微震活动比较平稳,能量集中区未对巷道形成直接影响;工作面来压周期平均2.4 d,来压步距14.5 m,未出现持续性高强度来压;顶板观测孔裂隙发育良好,有效半径可达4 m。

Based on the characteristics of thick hard roof and hard coal seam of rock burst mine in Ordos area,the occurrence process of rock burst under the condition of wide coal pillar mining was analyzed.It is revealed that the rock burst in this region is caused by the dynamic system instability in the high stress region of coal body,vibration,stress wave excitation,stress wave interaction with the coal body in the plastic region.Taking Bayangaole Coal Mine as an example,deep hole blasting was used to relieve the pressure on the roadway roof.The results showed that in the area where the roof was not broken,the limit breaking of the roof leaded to large energy micro-seismic events,the energy release was concentrated on the side along the empty roadway,and there was a phenomenon of dynamic pressure on site.In the normal fault roof area,the micro-seismic activity was relatively stable,and the energy concentration area had no direct impact on the roadway.The average pressure period of the working face was 2.4 days,the pressure step was 14.5 m,and there was no continuous high-intensity pressure.The crack of the observation hole in the roof was well developed,and the effective radius could reach 4 m.