Revisiting mathematical model of the process of self-destruction of outburst-hazardous coals under hydrodynamic impact

Abstract One of the options of self-destruction process model of outburst-hazardous coal seams under hydrodynamic impact (HDI) in the conditions of mines in the Donbas central region is considered. The model is based on the results of a comprehensive study of the parameters of the HDI process: mass and coal recovery factor; flow rate of technological boreholes and volume of extracted gas; the calculated degree of the massif degassing and the HDI degassing index from the coal hardness and the natural gas content of outburst-hazardous coal seams. The solution to this problem is connected with the lack of a model for coal destruction during HDI, which leads to an avalanche-like self-destruction of outburst-hazardous coals with the generation of methane. The phenomenon of methane generation is considered in the “coal-gas” system, which is a complex globular organization of macromolecules of outburst-hazardous coals. The model allows to consider the process of development of additional stresses around new formations and theoretically substantiate the presence of an additional source of gas release. To determine the stress-strain state, a solution to the spatial problem of elasticity theory is proposed for n successively arranged cylindrical cavities under the internal pressure action in an isotropic and homogeneous infinite medium is proposed. The dynamic component of the process is determined by the component of the stressed state of the elastic medium under the action of variable load and inertia forces in stressed gas-filled media. The research results are used in the development of technology of active degassing and coalbed methane production by hydrodynamic impact method.