Experimental Study On Energy Dissipation Of Coal And Gas Outburst

Coal and gas outburst is an extremely complicated mine gas dynamic phenomenon encountered in producing coal mining.It mainly manifests in an extremely short period of time,a large amount of coal-rock are thrown into the mining space from the coal-bed,accompanied by a large quantity of high-pressure gas jet,forming a high-speed coal-rock and gas flow.In this process,the gas internal energy is not only consumed in the throwing of the crushed coal body,but also will further pulverize the crushed coal body in the throwing process.From the perspective of energy,coal and gas outburst is a process of energy accumulation,transfer and dissipation.In order to study the law of energy dissipation in the outburst process,this paper has carried out a series of experiments,mainly including coals of different hardness The impact crushing test,different coal sample size,different adsorption gas,coal and gas outburst simulation test under different outburst pressure conditions,the statistical characteristics of the outburst coal body after outburst occurred were studied.Based on the statistical characteristics of the thrown coal,the energy dissipation during the outburst process was studied.Through the research in this article,the main research results are as follows:(1)In the process of coal and gas outburst,ground stress stimulated and gas pressure work together to strip and crush coal-bed and controls the expansion of pores and fissures in coal-bed,flows,and desorption of gas.The stripping and crushing of coal is the main driving force for coal throwing and crushing;based on the conservation of energy during the occurrence of coal and gas outburst,the energy dissipation during the occurrence of outburst is analyzed,and the energy produced for each portion is calculated.(2)The impact crushing experiment of lump coal was designed to study the relationship between crushing energy and newly added surface area,the fractal characteristics of coal after crushing and the relationship between fractal dimension and coal solidity coefficient.The results show that the crushing energy has a linear relationship with the newly added surface area,and the fractal dimension has an expected linear relationship with the crushing energy.(3)After simulation tests of coal and gas outburst under different pressures were designed,the results show that after the outburst,the wavy shapes of the coal thrown in the outburst mouth and the simulated roadway are similar.After coal and gas outburst excitation,the residual gas will continue to desorb and work on the outburst until there is not enough power to throw out the coal.The simulation test results of different gases show that CO₂ gas has a stronger ability to perform work on outburst than air.The further the throwing distance of outburst coal is,the larger the ratio of pulverization.Simulation experiments with different pressures show that with the increase of gas pressure,the throwing distance of outburst coal and the ratio of pulverization increase.(4)Through the energy analysis in the process of outburst occurrence,the gas expansion energy,coal throwing work and crushing work in the outburst process were calculated,and on this basis,the proportion of adsorbed gas participating in outburst work was analyzed.The higher the amount of gas involved in outstanding work,the higher the proportion.When the test gas is consistent with the outburst pressure,the gas desorption amount of the small particle size coal sample is greater than that of the large particle size coal.The expansion and release of internal energy plays an important role.Through the energy analysis in the process of outburst occurrence,the gas expansion energy,coal throwing work and crushing work in the outburst process were calculated,and on this basis,the proportion of adsorbed gas participating in outburst work was analyzed.The higher the amount of gas involved in outburst force,the higher the proportion is.When the test gas is consistent with the outburst pressure,the gas desorption amount of the small particle size coal sample is greater than that of the large particle size coal.In conclusion,it plays an important role for the expansion and release of gas internal energy.