煤层采掘活动引起断层活化的力学机制及其诱冲机理  

Mechanism of fault reactivation and its induced coal burst caused by coal mining activities

作　　者：蔡武[1] 窦林名[1] 王桂峰[1] 胡亚伟 CAI Wu;DOU Linming;WANG Guifeng;HU Yawei(Jiangsu Engineering Laboratory of Mine Earthquake Monitoring and Prevention,School of Mines,China University of Mining&Technology,Xuzhou,Jiangsu 221116,China)

机构地区：[1]中国矿业大学江苏省矿山地震监测工程实验室矿业工程学院

出　　处：《采矿与安全工程学报》2019年第6期1193-1202,共10页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51604270,51874292);国家重点研发计划项目(2016YFC0801407);煤炭资源与安全开采国家重点实验室自主研究课题项目(SKLCRSM15X04)

摘　　要：通过调研总结煤层采掘活动与断层赋存状态之间的概念模型,提出了采动应力主导和矿震动载主导两种断层活化类型的力学机制及其动静载叠加诱冲机理,并结合数值模拟、相似材料模型实验以及微震监测给予了验证,同时针对性探讨了断层冲击矿压的监测与防治方法及策略。结果表明,断层冲击矿压的发生机理是由断层与顶板结构双重作用形成的断层煤柱高静载与采动应力主导型或矿震动载主导型断层活化动载叠加诱发;其中,断层活化主要与断层面黏结力、断层摩擦角、断层倾角、最小主应力、孔隙压力有关,且开采扰动引起的水平采空侧卸载和竖直方向加载,即侧压系数降低,是采动应力主导型断层活化的力学本质;动载扰动作用产生的断层超低摩擦效应是矿震动载主导型断层活化的力学本质。研究结果对断层冲击矿压的监测与防治具有重要指导意义。In this paper, the relationships between coal mining layouts and fault occurrences have first been investigated to summarize the relevant conceptual models. Subsequently, the mechanisms of fault reactivations dominated by mining-induced stress and by seismic-based dynamic stress have been proposed, and the resultant induced coal bursts have been interpreted from the superposition point of static and dynamic stresses. These two types of fault reactivations have then been validated by the results of numerical modelling, similar material simulation and microseismic monitoring. On this basis, the corresponding monitoring methods and prevention strategies for fault-induced coal burst have been discussed. The results have shown that fault-induced coal burst is triggered by the superposition of the high static stress in the fault pillar resulted from the interaction of fault and roof structure and the dynamic stress from the fault reactivation dominated by mining-induced stress or by seismic-based dynamic stress. Moreover, the fault reactivation is mainly related to the cohesion, friction angle, dip angle of the fault plane, the minimum principal stress and the pore pressure. In particular, the decrease of the lateral pressure coefficient, dominated by the mining-induced stress with the vertical stress increasing and the horizontal stress decreasing, is the main mechanical essence of the fault reactivation. An ultra-low friction phenomenon generated from a dynamic loading is the main intrinsic mechanism of the fault reactivation dominated by the seismic-based dynamic stress. The results in this paper could be of great guiding significance for the monitoring and prevention of fault-induced coal burst.

关 键 词：冲击矿压 断层活化 采动应力 矿震动载 断层煤柱 

分 类 号：TD315[矿业工程—矿井建设]