正断层对顶板变形规律及冲击地压的影响分析

Influence Analysis of Normal Fault on Roof Deformation and Rock Burst

以常村煤矿25采区为工程背景,采区内有Fj239、Fj214和Fj245这3个正断层,断层落差小于2 m,倾角约为45°,从上盘垂直断层向下盘推进开采,通过数值模拟方法对采场顶板稳定性及冲击地压进行了研究。结果显示:随着工作面逐步推进,当不经过断层时直接顶及上覆岩层以拱形上移式塌陷,经过断层时直接承顶及上覆岩层沿结构面方向沉降变形;开采过程中能量容易集中在顶板断层及工作面处,断层越密集能量集中程度越高;工作面距断层越近工作面前方的超前支承压力峰值越大,且峰值位置有向工作面靠近的趋势。

Taking No.25 mining area of Changcun coal mine as the engineering background. There are three normal faults Fj239, Fj214 and Fj245 in the mining area. The fault drop is less than 2 m and the dip angle is about 45°. Advance mining from hanging wall vertical fault to down wall. The stability of stope roof and rock burst are studied by numerical simulation method. The results show that with the gradual advance of the working face, the direct roof and the overlying strata collapse in an arch shape without passing through the fault, and the direct roof and overlying strata will subside and deform along the direction of the structural plane when passing through the fault. In the process of mining, energy is easily concentrated in roof faults and working faces, and the more concentrated the faults, the higher the degree of energy concentration. The closer the working face is to the fault, the greater the peak value of advance support stress in front of the working face, and the peak position tends to be close to the working face.