Study on Mechanical Reaming and Rnloading Mechanism of Impact Ground Pressure Coal Seam

Mechanical reaming and pressure-relief can accurately reduce the stress concentration of shallow surrounding rock mass, which is of great significance to effectively solve the problem of decreasing stability of roadway surrounding rock caused by dense large-diameter drilling and pressure relief. Based on the engineering practice of the 3106 working face of a mine, ABAQUS finite element simulation software was used to compare and analyze the changes of vertical stress, displacement, and plastic zone of surrounding rock after pressure relief by large-diameter drilling and mechanical reaming, and study the mechanism of pressure relief by mechanical reaming. The results show that: After mechanical reaming, the peak stress of the surrounding rock decreases by 14.89%, the stress of the relief section decreases by 13% on average, and the peak stress shifts back by 1.25 m. The displacement at the roof of the roadway decreases by 28.67%, and the average displacement at the top, middle, and bottom of the roadway slope decreases by 98.71%, 97.27%, and 90.63%, respectively. The proportion of plastic strain zone is reduced to 12.92%, and the plastic zone between the adjacent holes around the mechanical reaming is connected to play a coupling pressure relief role. After field application, the mechanical reaming reduces the maximum microseismic energy by 63.11%, the pressure relief effect is good, and the impact risk of the working face in the test range is eliminated.