Experimental Study on Dynamic Evolution Mechanism during Coal and Gas Outburst

Abstract Coal and gas outburst is one of the most serious disasters in coal mining. To research the outburst evolution mechanism, we used the multi-field coupled coal mine dynamic disaster large-scale test system for simulating coal and gas outburst. In the present study, the evolution characteristics of gas pressure, temperature, and coal body stress during the outburst process were explored. Experiment results show that (1) the coal seam gas pressure decreased faster where the position is closer to the outburst, and the spherical shell-shaped outburst wave front formed in the coal seam propagated rapidly from the outburst outlet to the inside; (2) during the process of coal and gas outburst, the elastic energy of coal body released instantly, which slightly increased the temperature and then the gas desorption absorbed the heat, thereby slowly dropping the temperature; (3) after the outburst, coal and gas released the pressure, and the stress inside of the coal body decreased. The reduction of stress around the outburst hole was the most obvious.