采动应力下底板隐伏断层渗流场演化规律研究

Study on the Evolution Law of Seepage Field of Hidden Faults in the Floor under Mining Induced Stress

为探明采动应力作用对底板隐伏断层承压水导升趋势的影响,以芦子沟煤矿为例,采用FLAC^(3D)建立35°、55°、75°共计3种不同倾角的断层模型,采用fluid fl_isotropic模拟承压水渗流过程,对采动过程中的底板渗流矢量场,断层垂直应力与孔隙水压力的演化趋势进行分析。结果表明:在断层角度逐渐增加时,承压水活化程度与导升能力随之提升。采动应力下,承压水突破隔水层的水头位置一般滞后于采空区,合理地解释了底板突水的滞后特性。在时空分布角度上,工作面推进越靠近断层附近位置,越容易致使断层活化。在形态分布角度上,断层倾角越大,断层采动应力的跃升速度越快,对承压水的导升能力更强,表明断层倾角的增大对底板突水有激化作用。

To investigate the influence of mining induced stress on the upward trend of confined water in hidden faults of the floor,taking Luzigou Coal Mine as an example,using FLAC^(3D) to establish fault models of 35°,55°,and 75°with a total of 3 different dip angles.Fluid fl_isotropic is used to simulate the seepage process of confined water and analyzes the vector field of floor seepage,the evolution trend of fault vertical stress and pore water pressure during mining process.The results indicate that as the fault angle gradually increases,the activation degree and the guide and lifting ability of confined water increase accordingly.Under mining stress,the water head position of confined water breaking through the impermeable layer generally lags behind the goaf,which reasonably explains the lag characteristics of water inrush from the floor.In terms of spatiotemporal distribution,the closer the working face advances to the location near the fault,the more likely it is to cause fault activation.From the perspective of morphological distribution,the larger the dip angle of the fault,the faster the jumping speed of the mining induced stress of the fault,and the stronger its ability to guide confined water,indicating that an increase in the dip angle of the fault has an intensification effect on water inrush from the floor.