小断层活化会加剧采空区上覆岩层破坏增强渗透性，导致采空区煤自燃，针对这一问题，以河南神火煤电股份有限公司薛湖煤矿25030工作面为工程背景，利用UDEC数值模拟断层不同倾角、不同水平断距条件下采空区上覆岩层移动破坏过程，分析了断层对采空区上覆岩层破坏及渗透性的影响。研究表明：①随着工作面逐渐接近断层，断层出现滑移现象，断面附近位移呈斜向下趋势，下盘沿断层滑移比较明显；受到断层下盘滑移错位形成的支撑力影响，下盘下沉量明显大于上盘，上盘覆岩“三带”高度有所上升。工作面推过断层10 m时，上方覆岩位移开始出现滞后现象，且上盘下沉量小于下盘；工作面过断层40 m后，覆岩受到断层的影响逐渐减弱，位移逐渐符合无断层开采覆岩移动规律，下盘主要以下沉为主，上盘受到断层影响，楔形头部受到断层滑移的支撑，岩层垮落不充分，下沉量小于下盘。②倾角越大，断层对上盘覆岩支撑作用的影响范围越小，断层滑移形成的错位越严重，对开采危险性越大，且断层影响开始出现的位置距离越近；水平断距越宽，上盘受到断层的支撑力越大，过断层后上盘覆岩的位移越小；断层水平断距越宽，断层下盘下沉量越大，工作面过断层时危险性越大。③断层导致附近岩层孔隙率呈现跳跃式增大，倾角越大，孔隙率上升幅度越小；随着倾角的增加，断层正上方垮落带孔隙率呈先上升后下降趋势，在倾角45 °达到最大，而断裂带孔隙率随着断层角度的增加呈逐渐上升趋势；随着断层水平断距的增加，垮落带覆岩孔隙率大体上呈先上升后下降趋势，而断裂带的孔隙率略微上升。总体而言，水平断距越宽，断层倾角越大，工作面过断层时覆岩垮落危险性更大。

Taking the No. 25030 working face of Xuehu Coal Mine of Henan Shenhuo Coal & Power Co.,Ltd. as the engineering background, UDEC was used to simulate the movement and failure process of overlaying strata in the goaf at different dip angles and different horizontal fault distances, and the influence of faults on the failure and permeability of overlaying strata in goaf was analyzed. The results show that:①as the mining face approaches the fault gradually, the fault slips, the displacement near the section presents an inclined downward trend, and the footwall slips along the fault obviously. Under the influence of the supporting force formed by the footwall slip dislocation, the footwall subsidence is obviously larger than the hanging wall, and the height of the “three zones” of the overlying rock on the hanging wall was risen. When the mining face pushes through the fault for 10 m, the overburden displacement begins to lag, and the subsidence of the hanging wall is less than that of the footwall. When the mining face passes through the fault for 40 m, the overburden is gradually weakened by the fault, and its displacement gradually conforms to the movement law of overburden in fault-free mining. The footwall is mainly subsidence, the hanging wall is influenced by fault, and the wedge-shaped head is supported by fault slip. The rock strata collapse is not sufficient, and the subsidence amount is less than the footwall.②The larger the dip angle is, the smaller the influence range of fault on the hanging wall overburden support, the more serious the dislocation caused by fault slip, and the greater the risk of mining, and the closer the position where the fault influence begins to appear; the wider the horizontal fault distance, the greater the support force of the hanging wall by the fault, and the smaller the displacement of the hanging wall overburden after crossing the fault. The wider the horizontal fault distance, the greater the footwall subsidence of the fault, and the greater the risk of mining face crossing the fault. ③The porosity of nearby rocks increases by leaps and bounds. The larger the dip angle is, the less the porosity increases. With the increase of the dip angle, the porosity of the caving zone directly over the fault increases first and then decreases, and reaches the maximum at the dip angle of 45°, while the porosity of the fracture zone increases gradually with the increase of the fault angle. With the increase of the horizontal separation of the fault, the overburden porosity generally increases first and then decreases, while the fracture porosity increases slightly. Generally speaking, the wider the horizontal separation is, the greater the fault dip angle is, and the greater the overburden collapse risk is when the mining face crosses the fault.