Research on Dominant Factors and Control Technologies for Instability in Cross-Mining Roadway

To investigate the dominant factors and instability mechanism of surrounding rock deformation in cross-mining roadways, a systematic study was conducted using theoretical analysis, numerical simulation, and response surface methodology to examine the influence of various factors on surrounding rock stability. First, the theoretical model was refined by introducing a lithology coefficient of the load-transfer layer, thereby improving its engineering applicability. Subsequently, numerical simulations and response surface experiments were employed to analyze the effects of key factors, including the vertical distance between the working face and the roadway, the horizontal distance between the working face and the roadway, the burial depth of the roadway, the mining height of the working face, and the lithology of the load-transfer layer. The analysis results indicate that the vertical distance, horizontal distance, and lithology of the load-transfer layer are negatively correlated with roadway roof displacement, whereas the burial depth and mining height are positively correlated. The p-values for all factors were less than 0.0001. The order of significance of the influencing factors is as follows: vertical distance > horizontal distance > burial depth > mining height > lithology of the load-transfer layer. Among these, the vertical distance has the most significant effect on roadway deformation and exhibits notable interaction effects with burial depth and horizontal distance. Based on these findings, given that construction conditions cannot be altered, modifying the lithology of the load-transfer layer was selected as the control measure. Directional long-hole hydraulic fracturing for roof cutting and pressure relief was implemented in the roof of the return airway in the No. 6 mining district. Field monitoring results show that hydraulic fracturing effectively interrupted the stress transmission path induced by mining activities, transferring roof pressure to deeper strata. Consequently, the deformation of the surrounding rock was significantly reduced, the dynamic pressure effect was markedly alleviated, and the stability of the roadway was effectively controlled. The research results provide a theoretical basis for the design and control of cross-mining roadways under similar engineering conditions.