Stability evaluation and graded support technology of roadway roof surrounding rock

Taking Xiaobaodang No. 1 Coal Mine as the background, the distance from the stable rock stratum to the roof surface was selected as the core indicator, and a classification standard of Grades I to IV was established by combining factors such as rock stratum strength, thickness, and roadway span. FLAC^3D numerical simulation was used to analyze the stress distribution and plastic zone evolution of different roof grades during roadway excavation and mining stages, and a graded combined support scheme of bolts and anchor cables was designed and verified through theoretical calculations. The results show that the Grade I roof exhibits the best stability and a low roof fall risk, while the Grade IV roof exhibits the worst stability, is prone to high roof falls under mining disturbance, and presents significantly increased support difficulty. The classification method can effectively reveal the mechanical responses under different conditions and achieve a direct mapping between evaluation results and support parameters. The research results provide a theoretical basis and engineering guidance for the integrated design of quantitative roof stability evaluation and graded support, and are of great significance for reducing roof fall accident risks and improving coal mine safety and support efficiency.