Theoretical And Experimental Study On Energy Dissipation Of Coal And Gas Outburst

In recent years, China's total coal mining continues to increase, with the shallow resources reducing, the underground mining extends to deep, mining conditions are becoming more and more complex. So the gas power disaster occurred frequently, especially coal and gas outburst, bringing enormous challenges to the coal mining. However, the mechanism of coal and gas outburst, only in the hypothesis stage, is unclear now, and coal and gas outburst control has been limited. In order to deeply study the mechanism of coal and gas outburst, based on the combined effects of coal and gas outburst hypothesis, using a combination of theoretical analysis and experimental methods,analyzing the coal and gas outburst of energy dissipation mechanism. And according to the theoretical study and experimental analysis of coal and gas outburst, the mechanical model describing the coal and gas was established. The following results was obtained.(1) The energy dissipation of coal and gas outburst was analyzed from the theoretical aspect, getting the energy of coal and gas outburst comes from the elastic potential energy and gas energy of coal and rock, and the dissipated energy of coal and gas outburst include the crushing power, mobile power, and friction power and so on. What's more, the corresponding calculation formula was given.(2) Designing the mechanical power breaking coal experiment, different power provided by different times drop hammer, and the crushing case of outburst coal and non-outburst coal was studied. Then getting the new surface area of unit mass and energy are distributed by logarithmically, the equivalent diameter and energy are distributed by Power function.(3) The distribution of coal particles which the diameter is less than 0.075 mm during the mechanical power break coal experiment was analyzed. The results showing that the weight of these coal particles is small, but which owning enormous surface area. So it is inversely proportional that between the new surface area and coal particle size. Thus, the smaller the coal particle, the more new surface area, when the coal and gas outburst was occurred.(4) Developing the instant relief symmetry breaking coal experimental setup in the high-pressure gas. Both outburst coal, non-outburst coal, model coal of the unconstraint test and outburst coal, non-outburst coal of the constraint test was conducted. what's more, the result of the test was analyzed, the result showing that the crushing stage of coal is related to the physical and mechanical properties of coal, stress and gas. A tensile stress is applied to the coal when the instant relief high pressure; Coal and gas outburst is a temperature drop process.(5) Analyzing the stress distribution in front of the working face, establishing the mathematical calculation of stress distribution function, and depending on the accumulation of outburst coal in the roadway, owning the mathematical function expression of calculating the outburst coal strength. Then giving several hypothesis, based on the energy conservation principle, a mechanical model describing the coal and gas was established, obtaining the expression between coal and gas outburst and mechanical properties of coal, stress, gas and the structure parameters of roadway.