深部开采逆断层对冲击地压的诱导机制

Induction mechanisms of coal bumps caused by thrust faults during deep mining

基于逆断层形成机制,理论分析了逆断层周围的地应力环境,并以义马F16逆冲断层为工程背景,建立了其圆弧形态断层面的简化力学模型,得到了临近断层带两盘一定范围的应力分布特征;通过相似模拟实验观测了断层活化-失稳阶段对工作面冲击的物理过程,研究了冲击前后断层滑移与煤层应力变化规律;应用三维精细化数值模拟技术并结合现场实践,分析了临近F16逆冲断层典型冲击地压案例,揭示其发生的受力特征。综上研究表明:当上覆坚硬岩层阻挡软弱煤岩体沿断层面向上逆冲滑动时,临近断层带的坚硬煤岩体会产生应力集中,并在断层两盘一定范围内出现应力升高;临近断层回采过程中煤体所受的超前支承压力、断层支承压力、两盘失稳滑落对煤体冲击以及断层突然失稳破坏所产生的高能应力波会随着工作面与断层距离不同而产生不同的作用效果,按其一种或几种的叠加作用效果将逆断层诱发的冲击地压分为构造应力模式、断层活化模式与断层失稳滑动模式。从逆断层带地应力环境、采动影响下临近断层煤体受力特征与采动影响下断层活化-失稳滑动对工作面动载冲击效应方面,系统地揭示了逆断层对冲击地压的诱导机制,为逆断层诱发的冲击地压预警与防治提供参考。

Based on the formation mechanism of thrust faults,the crustal stress environment around thrust faults was theoretically analyzed. Taking the F16 thrust faults of Yima coalfield as an engineering background,a simplified mechanical model of thrust faults with cambered faults plane was built,and the stress distribution characteristics in a certain range near two sides of thrust faults were obtained. The physical variation process of coal face impacted by thrust faults which were at the stage of activation-instability and the change laws of faults slip and coal seam stress before and after the impact. The typical coal bumps cases of the F16 thrust faults of Yima coalfield were analyzed and its stress characteristics were revealed by the technique that combined 3 dimensional refined numerical simulation with fieldpractice. Results of those researches are as followed： when the upward thrust slip action of soft coal-rock mass was obstructed by hard overlying strata,the hard coal-rock mass will experience stress concentration,and an action of stress increase will occur in a certain range near two sides of faults. Stresses born by coal beam near faults during actual mining,including advanced abutment pressure,faults abutment pressure,impact stress of destabilization slide of two sides and high energy stress wave caused by abrupt destabilizing destruction of faults,take varied effects according to the different distance between workface and thrust faults. According to the different effects caused by one stress or the superposition of more stress sources,coal bumps induced by thrust faults were classified as tectonic stress field mode,faults activation mode and faults destabilizing slip mode. The induction mechanisms of coal bumps induced by thrust faults were systematically revealed from the aspects including： crustal stress environment in the area of thrust faults,coal beam stress characteristics of areas near to thrust faults under mining affection,dynamical impact effect of workface under mining affection caused by the slip of faults at the stage of activation-instability. The results of this research can provide references for the pre-warning and control of coal bumps caused by thrust faults.