Abstract:In response to the problem of large deformation of surrounding rock under the original support conditions of the return air roadway in the 1303 working face, which cannot meet the demand for efficient coal extraction in the mining face, it is proposed to comprehensively use technical means such as on-site measurement, drilling observation, and numerical simulation to analyze the causes of large deformation of surrounding rock, and provide an optimization plan for rock support. The analysis found that the main reasons for the large deformation of the surrounding rock in the 1303 return air roadway are the looseness of the surrounding rock, the expansion when encountering water, the lateral stress in the adjacent goaf, the water pouring in the surrounding rock, and the unreasonable original support parameters. Therefore, two optimization schemes, namely anchor rod+anchor cable+metal mesh, and anchor rod+anchor cable+metal mesh+grouting, are proposed for this purpose. Through numerical simulation analysis, the optimal scheme is to use anchor rod+anchor cable+metal mesh+grouting, and specific technical parameters for tunnel support are provided. After engineering application, the maximum convergence values of the top, bottom, and side of the return air roadway were 182mm and 63mm, respectively. The deformation values decreased by 72.7% and 85.8% compared to before support optimization, indicating that the optimized support scheme effectively controlled the deformation of the surrounding rock of the return air roadway.
