Quantitative analysis of energy competition in deep coal rock outburst-rockburst compound dynamic disasters

A novel experimental methodology was designed and true triaxial disaster-inducing tests with different simulation depths were conducted. The competition evolution mechanism of elastic energy and gas expansion energy during the disaster incubation has been explored. The results show that the types of compound dynamic disasters are primarily influenced by factors like stress, gas pressure and coal seam physical properties. As gas pressure varies, the gas expansion energy and elastic energy exhibit opposing evolutionary trends, leading to competitive accumulation between the two forms of energy. With increased relative outburst intensity, the crushing work increases while the average particle dimension decreases, leading to intensified coal pulverization and heightened destructiveness of outburst-rockburst events. The energy dissipation of the outburst-rockburst compound dynamic disaster is mainly attributed to the energy induced by the fracture and impact of the roof after outburst (58 %∼61 %), while that of the rockburst-outburst compound dynamic disaster is dominated by the crushing work (63 %∼70 %). Based on the energy conservation law, an energy criterion for outburst-rockburst compound dynamic disasters induced by instability of deep gas-bearing coal rock is established. By combining the proportions of coal rock release energy and gas release energy, the disaster-inducing transformation intervals are divided, and energy critical values are given.