关键词: 极近距离, 煤层群, 重复采动, 围岩力学特征

Abstract: In order to solve the problem that dynamic disasters are easily caused by repeated mining of very close coal seams, a comprehensive method of similarity simulation, numerical simulation and field application is adopted in this paper. The results show that when the roof and the goaf of the underlying working face are pushed to 85 m distance in the repeated mining process, the penetration area increases with the mining of the working face, resulting in irregular periodic weighting of the lower working face. The caving angle in front of the underlying working face decreases as a whole with the advancing of the working face, while the later caving angle increases, and the angle changes obviously when the working face advances to about 85 meters. Compared with the first mining, the stress concentration in the process of repeated mining is relatively mild and the influence range of pressure relief area is larger. But when the working face is pushed near the influence area of coal pillar in the first mining face, it is easy to cause the phenomenon of rapid stress growth and strong dynamic pressure. The preventive measures of strong dynamic pressure in working face under the condition of repeated mining of extremely close coal seam group with unified time-space-strength are put forward, which ensures the safety of working face.