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不同倾角和刚度下逆断层活化对煤矿冲击地压的影响

Influence of reverse fault activation on coal mine rock burst under different dip angles and stiffness

  • 摘要: 逆断层活化会加剧冲击地压发生危险,断层的倾角与刚度对冲击地压发生的能量积聚与释放具有控制作用。为分析不同断层倾角与刚度对煤矿冲击地压的影响,以义马矿区耿村煤矿赋存的F16逆断层为工程背景,综合运用理论分析、数值模拟、现场监测等方法,分析不同断层倾角和刚度对回采工作面应力场演化及断层活化失稳的影响规律。结果表明:当逆断层倾角超过60°时,逆断层的剪应力与垂直应力显著集中,导致滑移风险系数β增加,断层易进入活化状态;当断层刚度比<1/5时,工作面超前支承应力峰值升高,同时水平位移呈现非线性增长,在工作面前方形成“应力屏障”效应,加剧了煤体能量积聚,增加冲击地压危险。以F16逆断层为例,耿村煤矿13200工作面处于F16断层影响范围内。通过对F16断层活动性进行监测可知,在监测期间内,13200工作面回采期间内,由于F16受采动影响,断层发生活化,导致煤岩体内积累能量集中释放,诱发了5次大能量微震事件。为断层型冲击地压的预测与防治提供了理论依据与参考价值。

     

    Abstract: The activation of reverse faults can significantly increase the risk of rock burst, as the fault's dip angle and stiffness control the accumulation and release of energy that triggers such events. To assess the impact of varying fault dip angles and stiffness on rock burst risk in coal mines, this study uses the F16 reverse fault in Gengcun Coal Mine, located in the Yima mining area, as a case study. Through a combination of theoretical analysis, numerical simulations, and field monitoring, the study investigates how changes in fault dip angle and stiffness influence the evolution of the stress field in the working face and the activation-induced instability of the fault. The results show that when the dip angle of the reverse fault exceeds 60°, significant concentrations of shear and vertical stresses occur, increasing the slip risk coefficient (β) and making the fault more susceptible to activation. Additionally, when the fault stiffness ratio is below 1/5, the peak abutment stress ahead of the working face rises, and horizontal displacement grows nonlinearly, creating a “stress barrier” effect. This intensifies energy accumulation in the coal seam and elevates the risk of rock burst. Using the F16 reverse fault as an example, it is shown that the 13200 working face at Gengcun Coal Mine lies within the fault's influenced zone. Monitoring data from the F16 fault reveal that mining activities at the 13200 working face triggered the activation of the fault, leading to the concentrated release of accumulated energy in the coal-rock mass and the occurrence of five high-energy microseismic events. This study offers valuable theoretical insights and practical guidelines for predicting and preventing fault-induced rock burst.

     

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