Study on Spatial Distribution Characteristics of Pressure Relief in Coal Mine Goaf

In order to study the pressure relief distribution characteristics of coalbed methane in goaf, we use FLAC^3D software to simulate the three-dimensional stress distribution of the surrounding rock after excavation of coal seam. The distribution characteristics of the unloading space in goaf are divided based on the calculation results. The results show that the distance from the center of the coal seam increases, and the stress in the vertical direction increases sharply, then the velocity increases slowly until it approaches to the stress of the original rock; with the increase of the distance from the boundary of the goaf, the triaxial stress on the coal pillar increases sharply first, then decreases sharply and gradually tends to the original rock stress; the overall distribution of the unloading space in goaf is approximately “crab”, and the unloading space of the goaf in the upper part of the coal seam is obviously greater than that in the lower part.