Study on Spatiotemporal Evolution Laws of Anti-outburst Effect Area of Upper Protective Layer Mining

In the mining of coal seam group, it is the most effective measure to improve the permeability of coal seam by utilizing the effect of “pressure relief and permeability improvement” produced by mining in protective layer. Based on the method of theoretical analysis and numerical simulation, this paper studies the spatial and temporal distribution of the stress and strain of the rock in Guizhou Mining Area. The results show that there are stress concentration zone, transition zone and pressure relief zone after mining protective seam; and the maximum deformation amount of the pressure relief zone is 82.7 mm according to the established equation. It is restored with the protective seam mining that the stress (strain) and deformation in the area of the protected coal seam, indicating that the effect of pressure relief and permeability improvement has the spatiotemporal difference. The maximum deformation of the protected coal seam is 80 mm, which is consistent with the theoretical result.