深部构造区大倾角工作面回撤致冲机理及防治技术

Mechanism and prevention technology of large inclined workface retracement inducing rock burst in deep tectonic zone

深部构造区大倾角工作面回撤期间冲击风险较高,为研究回撤期间致冲机理及防治技术,以潘西煤矿6199工作面为背景,采用理论分析、数值模拟,结合现场数据开展研究。结果表明:工作面受多因素影响处于复杂高静载环境,上部基本顶尖角区剪应力集中明显,工作面液压支架撤离,上覆岩层压力向工作面前方转移,局部超过极限载荷可能发生高静载加载型冲击,基本顶破断及断层活化产生动载,可能诱发动静载叠加型冲击;根据回撤前矿压数据,前方岩层活动较为剧烈,工作面微震预警事件发生前后支架阻力升高,存在基本顶破断及断层活化可能,冲击风险较高。基于回撤致冲机理提出卸压-支护协同防冲技术,即通过弱化高静载影响,降低动载产生可能性,辅助提高顺槽支护强度、控制工作面顶板降低回撤期间冲击风险;工作面回撤期间矿压监测数据无明显升高,卸压-支护协同防冲技术效果较好。

The risk of rock burst during the retracement of large inclined workface in the deep tectonic area is high,in order to study the mechanism of rock burst and prevention and control technology for the retracement of the workface,the research is carried out by theoretical analysis and numerical simulation with the background of 6199 workface of Panxi Coal Mine.It was concluded that:the workface is in a complex high static load environment under the influence of many factors,the shear stress concentration in upper basic top corner is obvious,the hydraulic support of the workface is retreated,the pressure of the overburden rock layer is transferred to the front of the workface,the high static load loading type rock burst may occur locally exceeding the limit load,and the activation of the basic roof broken and faults generates the dynamic load,and it may induce the dynamic and static load superposition type rock burst;the mine pressure data before the retracement indicate that the rock activity ahead is more intense,the resistance of the support increases before and after the occurrence of the working face micro-seismic warning event,there is a basic top break and fault activation may be,the risk of rock burst is high;based on the mechanism of rock burst during the retracement period,it is proposed to decompress-support cooperative prevention technology of rock burst,by weakening the influence of the high static load and decreasing the possibility of the dynamic load,and it assists in increasing the strength of the support of the tunnel of the workface,and controlling the roof of the workface to reduce the risk of rock burst during the retraction period.During the retracement of workface,there is no obvious increase in mine pressure monitoring data,and the effect of decompress-support cooperative prevention technology is good.