Numerical simulation study of roof cutting and roadway protection under the condition of deep dynamic pressure

Abstract

In order to study the difficulty of supporting the surrounding rock in the mining area due to the dynamic pressure of the working face, the Daqiang coal mine is used as the background to study the key parameters of the cut-roof roadway protection using the method of theoretical analysis and numerical simulation. Theoretical analysis shows that the destruction of the surrounding rock of the main roadway in the mining area is mainly affected by the stress of the deep plateau rock and the mining stress of the adjacent working face. Using deep-hole energy-accumulating blasting technology to cut the roof of the retreat channel at the end of the adjacent working face in advance, not only can effectively prevent the transfer of mining stress in the working face, but also protect the purpose of the retreat channel and the main roadway in the adjacent mining area. Numerical simulation studies have found that: (1) when the top cutting height reaches the basic top position and the top cutting angle is about 30°, the protection of the surrounding rock of the retreat channel and the adjacent main roadway is the most effective; (2) Too early or too late cutting time will also affect the effect of preventing the transfer of mining stress, thus failing to achieve the purpose of cutting off the transfer of mining stress to adjacent roadways. Therefore, finding the right top-cutting time is also very important; (3) If a support body that can provide high prestress and withstand large deformations of surrounding rock is applied in the main roadway of the adjacent mining area, the support body and the surrounding rock can be coupled, so that better stability control effect can be achieved.. This research can effectively provide help for the stability design of main roadways affected by dynamic pressure.