大断层采动“活化”导水特性研究

Study on characteristics of activating to conduct water in large-scale fault under mining

煤层回采引起的断层"活化"导水是矿井突水的一种重要形式,具有很高的危险性和隐敝性。依托具体的工程背景,建立简化的力学模型和数值模型,根据弹塑性力学和裂隙介质水动力学理论分析不同推进距离时断层面上的主应力和法向应力变化情况,并通过模拟计算得出回采过程中应力变化与塑性破坏特征。研究结果表明,新集矿区F10大型断层在煤层推进至距断层20 m位置时开始有"活化"趋势,断层带岩体位移值陡增到0.05 m,距10 m时断层面主应力急剧增大,峰值应力向浅部转移,断层带发生明显位移,孔裂隙扩张。为保证生产安全,需预设30 m防水煤柱,避免煤岩体突水通道沟通主干断层及承压含水层,该研究成果可为矿井生产提供一定的参考价值。

ctivating to conduct water of fault is an important form of mine water inrush caused by coal mining,and has very high risk and concealment. A simplified mechanical and numerical model was built based on specific engi-neering background,the principal stress and normal stress of fault plane were analyzed by different mining step ac-cording to the theory of elastic-plastic mechanics and fissure medium hydrodynamics,and the characteristics of stress change and plastic failure in mining process were obtained by simulating calculation. The results showed that F10 large-scale fault in Xinji colliery had activity trends when excavating seam to 20 m from fault,and rock mass displacement value of fault zone sudden increased to 0. 05 m. When being 10 m from fault plane,the principal stress increased rapidly,the peak stress gradually transferred to the shallow part,and the fault zone had obvious displacement,pore and fissure expansion. In order to ensure the safety of production,30 m waterproof coal pillar should be preseted to avoid the water inrush connecting major fault and confined aquifer,and the results of the study can provide some reference value for mine production.