两煤层坚硬顶板联动冲击致灾机制

针对宽沟煤矿“3·7”、“3·8”震动事件呈现短时间隔“连锁”效应的现象,采用现场实测方法研究两煤层开采后的岩层结构特征,采用理论分析、微震监测的方法分析了两煤层开采形成的结构形态与失稳演化过程,基于数值模拟方法揭示了两煤层开采坚硬顶板联动效应引起的煤体应力演化过程,提出了两煤层联动冲击致灾机制。研究表明:I010203面形成了侧向悬顶的结构,实测确定了结构Ⅰ的悬顶长度为18.5~37.5 m,两煤层坚硬顶板呈现由低位向高位、煤柱侧向实体侧失稳的演化过程,揭示了两煤层坚硬顶板联动演化过程;通过数值模拟、采前PASAT探测获得了结构Ⅰ和结构Ⅱ联动过程的应力演化特征,认为岩层结构的变化是煤(岩)体应力的演化的重要原因,联动过程临空巷道应力不断升高,加剧了工作面冲击危险性;两煤层开采扰动致使坚硬顶板联动,剧烈释放结构Ⅰ与结构Ⅱ积聚的弹性能,诱发高静载条件的临空巷道冲击显现或局部巷道变形。

Disaster mechanism of two coal seam hard roof linkage impact

With"March 7","March 8"mine tremor in Kuangou Coal Mine presenting a short interval of the phenomenon of"chain effect",by adopting the method of in-situ test study after two coal seams mining strata structure features,by using the method of theoretical analysis,seismic monitoring of two coal seams were analyzed by structure forms and instability of evolution process,based on the numerical simulation revealed the two coal seams hard roof linkage effect caused by the stress evolution process of coal,two linkage mechanism of causing an impact of coal seam was put forward in this paper.The results showed that,the I010203 working face formed a lateral suspended roof structure.The measured length of the suspended roof of structureⅠwas 18.5~37.5 m.The hard roof of the two coal seams presented an evolution process from low to high and coal pillar to solid side,revealing the joint evolution process of the hard roof of the two coal seams.The stress evolution characteristics of the linkage process of structureⅠand structureⅡwere obtained through numerical simulation and PASAT detection before mining.It was believed that,the change of rock strata structure was an important reason for the evolution of coal and rock mass stress.The stress of the roadway increases continuously in the linkage process,which increased the impact risk of the working face.The mining disturbance of the two coal seams caused the linkage of the hard roof,which dramatically released the elastic energy accumulated by structureⅠand structureⅡ,and induced the impact appearance or local roadway deformation of the facing roadway under high static load.