Multi-scale modeling and sensitivity analysis for weak roadway areas: A case study of Xiaoyun coal mine

Ground control in deep coal mine roadways faces significant challenges due to the presence of “weak zones” characterized by complex stress environments and structural incompatibilities. To differentiate the failure mechanisms of these zones and optimize support strategies, this study integrates theoretical analysis, multi-scale numerical simulation, and field monitoring, using the 6204 track roadway at Xiaoyun Coal Mine as a case study. A macro-meso coupled numerical model was constructed to simulate fracture evolution, and an orthogonal experiment utilizing Range Analysis and Analysis of Variance (ANOVA) was conducted to evaluate the sensitivity of support parameters. The results indicate that bolt spacing is the most critical factor controlling plastic zone propagation, significantly outweighing geometric parameters like bolt diameter or length. Based on these findings, a synergistic support strategy combining “dense high-strength bolting” and “deep-anchored cabling” was proposed. Numerical evaluations suggest that this scheme limits the plastic zone depth by 40% (to approximately 1.5 m), substantially mitigating confinement blind spots. Field monitoring indicates that the optimized support system successfully restrains the cumulative residual roof subsidence to approximately 31.9 mm and the sidewall convergence to approximately 22.8 mm, effectively promoting the long-term overall stability of the roadway.