Research On Space-time Cooperative Outburst Prevention Technology Of Coal And Gas Co-mining In Over-protective Seam Of Three Soft Coal Seam

In recent years,the proven reserves of mineral resources in China have increased year by year.In the structure of primary energy consumption,the proportion of coal resources has decreased year by year.At present,coal energy accounts for about 60% of the disposable energy consumption,which is the most important part of China's energy consumption.In a long period of time,the main pattern of coal resources in China's energy will remain unchanged.With the continuous increase of mining depth,coal and gas outburst has become one of the main disasters threatening the safety of coal mine production.Due to the small Proctor coefficient of three soft coal seams and their adjacent roof and floor,the problem of coal and gas outburst is particularly serious.In order to solve the problem of coal and gas outburst in three soft coal seams and realize the safe production of the mine,this paper takes zhujixi coal mine as the object,through the construction of coal rock gas solid coupling dynamic model,using COMSOL multiphysics 5.2 numerical simulation software to carry out the numerical simulation of the mining of the upper protective layer under different geological conditions and the numerical simulation of the extraction effect of different gas extraction methods,and puts forward different places Under the condition of coal and gas CO mining,the scheme of time and space coordinated outburst prevention technology is proposed.(1)Based on creep theory,a gas-solid coupling model of coal-rock gas is proposed,and geometric equations,equilibrium differential equations and constitutive equations are constructed to determine the coupling relationship between gas seepage and coal-rock layers.(2)By constructing the numerical model of the upper protective layer mining,the variation law of the protected coal seam stress and the law of sexual transformation in the upper protective layer mining process with different propulsion distance and different coal seam spacing are simulated.The pressure relief range of the upper protective layer mining is divided.The gas pressure relief effect of different gas drainage methods was studied by constructing a numerical model of gas drainage.(3)According to the different geological conditions constructed by the simulation,the time-space cooperative outburst prevention technology scheme of coal and gas is designed,and the 11-2 Coal Seam and 8 coal seam of zhujixi mine are taken as the object of engineering application,which effectively reduces the gas pressure of coal seam,gas content of coal seam and drilling cuttings,and eliminates the risk of coal and gas outburst of protected coal seam.