Based on the engineering problem of large deformation and support failure in the roadway of Ronghua No. 1 Mine, on-site in situ stress testing was carried out to understand the distribution characteristics of the in situ stress around the roadway. Then, a stability analysis of the roadway was conducted on the key factors causing support failure. Combining the on-site situation and the results of the stability analysis, the principle of surrounding rock stability control in a high horizontal stress roadway was proposed. Based on this principle, an optimized scheme was designed. The optimized scheme and the original scheme were comparatively analyzed through numerical simulation to verify the applicability of the optimized scheme. Finally, the optimized scheme was applied on-site, and the roadway was monitored. The results were as follows: (1) from the results of the in situ stress test conducted in Ronghua No. 1 mine, the horizontal tectonic stress field is dominant. (2) Based on the characteristics of in situ stress distribution, the angle between the direction of the maximum horizontal principal stress and the roadway orientation, along with varying lateral pressure coefficients, is directly proportional to the stress and deformation of the surrounding rock. (3) Through numerical simulation analysis, an optimized support scheme was proposed based on the original design. The roof subsidence was reduced by 37.3%, the floor heave was reduced by 49.5%, and the side convergence was reduced by 34.7%. The surrounding rock stability of the roadway was significantly improved. (4) The optimized support scheme was applied in the 6A# Left Second roadway at Ronghua No. 1 Mine. Through on-site monitoring of the perimeter rock deformation, significant reductions in deformation and increased stability were observed. The research content provides a theoretical basis and practical experience for the stabilization of high horizontal stress roadways.

The heterogeneous occurrence of coal-seam thickness represents a common geological characteristic in underground mining. Variations in coal thickness can directly alter the instability-failure behavior of coal–rock systems, thereby triggering various dynamic disasters. Therefore, revealing failure and disaster-inducing mechanisms of coal–rock systems dominated by coal-thickness effects is critical for deep mining engineering design as well as dynamic disaster prevention and control. To this end, uniaxial compression tests combined with acoustic emission (AE) monitoring were performed on coal–rock combinations with different coal thicknesses. The evolution laws of characteristic strengths (uniaxial compressive strength, initiation strength, and damage strength) versus coal thickness were systematically analyzed. Using full-process spatial localization of internal damage derived from absolute AE energy, an instability evolution model for coal–rock combinations was established. Furthermore, intrinsic disaster-inducing mechanisms governing coal–rock system instability under coal-thickness regulation were summarized, with corresponding engineering prevention-control suggestions put forward. The results show that: (1) UCS, initiation strength, and damage strength of specimens exhibit a nonlinear negative correlation with coal thickness. Initiation strength and damage strength account for approximately 50% and 75% of UCS, respectively; (2) Increasing coal thickness weakens the confinement effect of upper- and lower-sandstone, which shifts the dominant failure zone gradually from coal–rock interfaces to coal interiors. Meanwhile, internal energy accumulation-release processes of combinations present staged evolution characteristics; (3) Different coal thicknesses produce distinct disaster-evolution paths for coal–rock systems. Larger coal thickness corresponds to higher risks of high-energy dynamic disasters. Accordingly, a differentiated hierarchical prevention strategy of “thin protection, medium pressure relief, and thick control” was proposed. These findings provide a theoretical basis for mine engineering design and dynamic disaster prevention-control under dominant coal-thickness effects.

Aiming at the technical problem of asymmetric large deformation of mining roadways under the influence of fault tectonic stress and excavation disturbance, and taking the return roadway of the left first face of 14^# coal seam in the East No.2 Mining Area of the Pinggang Coal Mine as the engineering background, this research on the deformation mechanism and control technology of a near-fault roadway was carried out by combining on-site monitoring, theoretical analysis, numerical simulation and on-site practice. The results show that under the superposition of fault tectonic stress and excavation disturbance, the surrounding rock presents asymmetric deformation characteristics of fault sidewall > roof > floor > mining sidewall, with the roof-to-floor convergence peak of 991 mm and the two-side convergence peak of 968 mm; the critical instability range of the near-fault roadway is nonlinearly negatively correlated with the surrounding rock Geological Strength Index (GSI) and nonlinearly positively correlated with the disturbance factor (D). The critical instability range of this roadway is 3.44 m, and the peak values of stress and deformation of pillars during the excavation and mining are concentrated 0~4 m from the sidewall; the pillar width is linearly negatively correlated with the stress peak and nonlinearly negatively correlated with the deformation peak. When the pillar width is greater than 16 m, the stress superposition effect of the fault and mining is weakened, and the surrounding rock deformation tends to be stable. Based on the deformation mechanism, a control scheme of “coal pillar size optimization + surrounding rock grouting modification + high-strength anchor cable strengthening” was proposed, which optimized the pillar width to 16 m, adopted grouting reinforcement, and added long and short anchor cables to form a high-strength active support system. On-site practice shows that after the application of this scheme, the two-side convergence and roof-to-floor convergence of the roadway are reduced by 82.4% and 84.5%, respectively, compared with the original support; during the mining period, the two-side convergence is 397 mm and the roof-to-floor convergence is 484 mm, realizing the safe and stable operation of the roadway and the efficient mining of the working face. The research results provide a theoretical basis and engineering reference for the control of asymmetric large deformation of typical near-fault roadways.