Experimental study on the influence mechanism of gas seepage on coal and gas outburst disaster

By using the self-developed triaxial servo-controlled seepage equipment for thermo-fluid–solid coupling of coal containing gas and the self-developed coal and gas outburst simulation test device, experiments to study the influence mechanism of gas seepage on coal and gas outburst disasters. The results show that: (i) gas seepage decreases the strength of coal containing gas and accelerates its failure process; (ii) under the same gas pressure, the confining pressure is larger, the more difficult the gas flows and the greater the intensity of coal containing gas is; (iii) in the process of coal and gas outburst, the greater the vertical ground stress is, the more powerful the outburst will be; (iv) the influence mechanism of gas seepage on coal and gas outburst disasters is as follows: firstly, gas seepage weakens the mechanical properties of coal body, which makes it much easier for coal and gas outburst to occur; secondly, on the same effect of external force, it will be easy to form a high gas pressure zone in the coal body under the difficult condition of gas seepage, and accumulate more gas compression energy, which is the energy source for coal and gas outburst, and it is also the main dynamic source to throw and grind the coal.

► The influence mechanism of gas seepage on coal and gas outburst disasters has been studied.
► Gas seepage is an essential factor for coal and gas outburst disasters.
► Gas seepage decreases the strength of coal containing gas and accelerates its failure process.
► The more difficult the gas flows, the more powerful the outburst will be.
► Gas compression energy is the main dynamic source to throw and grind the coal.