Surrounding Rock Deformation Failure Mechanism of Large Section Gateway with Top Coal in Coal Mine

To solve the problem of large section gateway support with top coal in coal mine, surrounding rock deformation and failure mechanism of Wangzhuang Coal Mine 7105 working face haulage way were studied through theoretical analysis and numerical simulation, and plastic zone, displacement field, stress field distribution evolution laws with different sections, top coal thickness without support were analyzed. The result shows that the top coal thickness has great influence on the stability of the gateway, as the thickness increases, the roof subsidence will grow; with the increase of gateway section, the surrounding plastic zone expands correspondingly, and change of gateway sides and roof will rise, but the floor does not change significantly; proper reduction of top coal thickness as well as the augment of gateway height will effectively control the deformation of roof, but we have to strengthen the gateway sides support; and the width of roadway increases, the roof displacement will go up then the anchor cable has to be adopted to strengthen the roof. Field monitoring results showed that the support scheme based on this conclusion controlled surrounding rock deformation effectively.