Mining Pressure Distribution Law and Disaster Prevention of Isolated Island Working Face Under the Condition of Hard “Umbrella Arch”

Aiming at the problem of safe mining of coal seam under the condition of hard roof, taking Xiagou coal mine as the background, the expression of coal seam supporting force in isolated island working face mining is derived through the analysis of the “umbrella arch” overlying rock structure mechanism in isolated island working face mining. Combined with the mine geological conditions, it is concluded that the supporting force near the inclined gob of ZF2822 isolated island working face is more than 1.26 times that near the strike gob. Based on the numerical simulation analysis, it is known that the stress and elastic energy of the working face near the inclined gob are obviously greater than that towards the gob, and the peak stress on the side of the transport gateway after the first square and the second square is 1.41 times and 1.55 times that of the return air gateway, respectively. Strata discrimination determines that the key stratum is medium-grained sandstone 22.32 m above the coal seam. The reasonable blasting pressure relief angle is determined according to the field situation. Pressure relief control makes the “high energy-high frequency” feature of mining face change into “low energy-low frequency”. After pressure relief, the daily average microseismic energy of working face mining is reduced to below 104 J, which is 27.77