Abstract:Addressing the problem of low strength and difficult control of fractured roof strata following secondary diagenesis during close-distance coal seam mining, an orthogonal experimental design was employed to investigate the influence of various support factors on the compressive strength of specimens. The results indicate that the optimal scheme achieving the highest specimen strength is: 2 rock bolts, bolt diameter of 12 mm, bolt embedment ratio of 2∶ 3, with mesh reinforcement installed. Sensitivity analysis revealed that bolt quantity exhibits significant sensitivity, while bolt diameter, embedment ratio, and mesh reinforcement demonstrate negligible in- fluence on specimen strength. Stress-time, acoustic emission count-time, and cumulative energy-time curves demonstrate that appropri- ately increasing bolt quantity can restrict crack propagation velocity. However, upon specimen failure, this configuration generates more fractures and releases greater energy. Bolt quantity effectively controls the fragmentation degree of the reinforced surface, while the failure pattern on specimen sides is influenced by the embedment ratio. Shear-compression cracks dominate the specimen failure process, with fractures spreading from the four corners toward the center and ultimately coalescing, leading to bolt failure.