Study on Overburden Movement Deformation and Roof Breakage Law of Under-Protective Steeply Inclined Coal Seam Mining

Abstract

The occurrence of a steeply inclined coal seam is extraordinary, and the coal body is seriously damaged by extrusion. The most steeply inclined coal seam is a high-gas or -outburst coal seam, and protective layer mining is the safest and most effective measure for regional prevention of coal and gas outburst. Based on considering the coefficient of lateral pressure and vertical height of the section, the deflection of the basic roof of the steeply inclined protective layer in a mine in western Henan, China, was calculated using the deflection calculation method of the thin-plate theory of elasticity. Using MATLAB to understand the deflection, the deflection curve was obtained. The law of rock movement and deformation in the mining process of the protective layer was studied by a similarity simulation experiment. The results show that, after mining, the roof mainly sinks slowly without large-scale collapse, and the largest rock strata movement is located in the upper part of the slope. Rock strata movement and fracture development can relieve the pressure of the protected layer and provide a channel for gas migration and drainage. The mining conditions of the protected layer will not be destroyed, and mining this type of protected layer in this mine has better safety and feasibility. The conclusions of this study have a guiding and scientific significance for the control of surrounding rock and the layout of gas drainage boreholes of under-protective steeply inclined coal seam mining.