Coupling mechanism between mining-induced deformation and permeability of coal

The coupling mechanism between mining-induced mechanical behavior and gas permeability of coal is effectively obtained in laboratory. This study means significant understanding of the prevention of coal–gas outburst. The testing samples of coal were drilled from the 14120 mining face at the depth of 690 m. Based on the redistribution of stress during the excavation, the coupling test between mechanical state and seepage has been designed using the triaxial servo-controlled seepage equipment for thermo-fluid–solid coupling of coal containing methane. It is the result that there are two main factors influencing the mining-induced mechanical behavior of coal, such as the change of σ1-σ3σ1-σ3 and Δσ1-Δσ3Δσ1-Δσ3. The failure mode mainly depends on the value of σ1-σ3σ1-σ3, and the peak strength value mainly depends on the value of Δσ1-Δσ3Δσ1-Δσ3. The difference of mechanical response between geostress and mining-induced stress has been obtained, which can be a theoretical support for safe mining such as reasonable gas drainage, prevention of coal–gas outburst and gas over-limit.