From Stress Redistribution to Energy Accumulation: Lateral Pressure-Driven Chain Evolution in Gas-Bearing Coal

As coal extraction advances to greater depths, a refined understanding of the coupled evolution of involved physical effects and mechanisms in gas-bearing coal under excavation-induced disturbances becomes indispensable. In this context, “chain evolution” characterizes the progressive and interdependent interplay among stress redistribution, damage propagation, and seepage adjustment. Building upon a seepage–stress–damage coupling model for gas-bearing coal, and supported by triaxial compression tests for validation, this study explores multifield evolution during roadway excavation across lateral pressure coefficients $\left(\xi \right)$ of 0.5, 0.8, 1.0, 1.2, and 1.5. The results reveal that the lateral pressure coefficient fundamentally regulates both the orientation and intensity of this coupled process by reshaping the initial stress regime and associated unloading constraints. At relatively low values $\left(\xi <0.8\right)$, damage and high-permeability zones preferentially propagate along the sidewalls, facilitating rapid gas pressure dissipation. Under near-equilibrium conditions $\left(0.8\le \xi \le 1.2\right)$, the stress, damage, seepage, and energy fields evolve in a coordinated, annular configuration surrounding the roadway. By contrast, at higher coefficients $\left(\xi >1.2\right)$, damage localization and permeability enhancement are concentrated in the roof and floor, accompanied by pronounced vertical energy accumulation. These findings underscore that the lateral pressure coefficient not only governs the spatial distribution of individual physical fields but also orchestrates the pathways of their coupled evolution. The study thus provides a robust, mechanism-oriented basis for optimizing support design and implementing targeted hazard mitigation strategies in deep gas-bearing coal seams.