Research on the Mechanism of Roof Damage and Control Technology of Air-Side Retaining Tunnel in Close Range Goaf
Taking the 3411 working face goaf of Xinyuan Coal Mine as an example,the failure mechanism and control technology of close range coal seam goaf were analyzed.The stress distribution law of the upper coal seam after mining was calculated based on elastic theory,and verified through FLAC3D numerical simulation.Calculate the depth of damage to the bottom plate of the coal seam,based on the"block dispersion"structure,analyze the damage process of the roadway roof under the closed goaf.During the excavation process of the roadway,it is recommended to use support methods such as U-shaped steel expansion brackets and backfill on the back wall,and control the surrounding rock of the empty roadway by installing roof anchor rods,reinforcing the backfill area roof,and using internal backfill technology.The results indicate that the maximum subsidence of the roof of the reserved goaf side entry roadway along the goaf is 180 mm,and the maximum proximity distance between the two sides is 328 mm,which meets the requirements of the working face operation.
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