Research On Deformation And Failure Law Of Gas-Bearing Coal In Wuhai Mining Area

The mechanical properties of gas-bearing coal-rock mass play an important role in controlling the occurrence and development of coal and gas outburst.With the increase of mining depth,the failure mechanism of gas bearing coal and rock mass will be transformed.The western mining area is a key development area of national coal resources,and there have been many high gas mines.Wuhushan Coal Mine is located in Wuda District,Wuhai City,Inner Mongolia,with a mine field area of 8.08 square kilometers.With the deepening of mining,it is also faced with the damage of gas to the coal rock mass.This paper adopts the research method combining theoretical research,experimental test and numerical analysis,and takes rock mass mechanics,statistical damage and continuum mechanics as the theoretical guidance.Select the coal samples from Wuhushan coal mine in Wuhai Mining Area to carry out the uniaxial compression experiment of gas bearing coal,find out the differences of uniaxial compression failure mechanical properties of coal samples under different gas pressure,and deeply analyze the influence of gas pressure on the mechanical properties of coal samples.Taking the SAW-2000 rock mechanics testing machine as the carrier,combined with the gas-containing coal uniaxial compression device and aeration system and the SAEU2S multi-channel acoustic emission signal analyzer,the mechanical parameters and acoustic emission of the coal samples under different gas pressures during the load failure process were analyzed.Signal parameters are measured and analyzed.Through experiments,it was found that with the increase of gas pressure,the compressive strength and elastic modulus of coal samples decreased,and the Poisson’s ratio increased.The cumulative energy of the harmonic emission showed a decreasing trend,and showed an obvious linear relationship.Using RFPA^2D gas version to simulate the failure process,mechanical parameters,acoustic emission spatial distribution characteristics,etc.of coal samples under different gas pressures,it is found that more random cracks are derived,more broken units,and the damage degree of the coal sample is greater,and the acoustic emissions range gradually expands;with the increase of gas pressure,the strain and peak strength of the simulated coal sample are both higher.It can be seen that the increase of gas pressure can weaken the bearing capacity of gas-containing coal;the acoustic emission peak count,acoustic emission cumulative number,acoustic emission peak energy and acoustic emission cumulative energy of the simulated coal samples all show a decreasing trend.The numerical analysis results are in good agreement with the experimental test results.The study on the differences of mechanical properties and the law of deformation and failure of gas-bearing coal in Wuhushan Coal Mine is the preliminary work of in-depth research on the mechanism of coal and gas outburst in Wuhai mining area.The prevention and control of coal and gas outburst accidents in mining areas and the drainage of coal seam gas under the influence of mining have important theoretical significance and practical value,and also lay a certain theoretical foundation for coal and gas co-mining in western mining areas.