关键词: 近距离煤层群, 低氧现象, 浅埋深煤层, 漏风通道, 水力压裂

Abstract: In view of the frequent occurrence of low oxygen in the return air corner of Shendong mining area, from the perspective of structural characteristics of overlying strata in goaf of shallow buried depth and close distance coal seam group mining, the 22104 working face of Shangwan Coal Mine was taken as an example, and the PFC discrete element software was used to simulate and study the variation law of rock caving, fracture development and stope stress in the mining process. The results show that under the occurrence condition of shallow buried depth and close distance coal seam group, cracks can develop to the surface, forming through air leakage channel; the mining of lower coal seam can lead to the formation of composite goaf, and at the same time, it has a significant activation effect on the old caving space in the upper part. The development degree of fractures increases, which aggravates the surface air leakage. The mining of the upper coal seam will cause a large pressure relief of the roof of the lower coal seam, which makes the roof of the goaf not easy to collapse and is easy to form a large area of suspended roof. The low oxygen prevention and control system combined with goaf air leakage control, working face pressure regulation and forced roof caving was proposed and established to solve the problems of serious surface air leakage, low oxygen gas emission in composite goaf and sudden collapse of large area suspended roof, respectively, and effectively solve the low oxygen problem in the return air corner of working face.