Study On The Gas Drainage Width Of Roadway Under The Coupling Of Stress And Seepage

Determining the gas drainage width of roadway accurately has an important significance to determine the depth of the coal samples.Firstly,the mechanical properties of the roadway are analyzed in the paper.The mechanics model of coal around the roadway considering the characteristics of plastic softening and expansion is established.And the expression of stress,volumetric strain and relieved pressure range of coal around roadway are obtained.The relieved pressure range of the coal body around the roadway under different coal conditions are determined.Using Darcy's law and gas content equation an so on,the seepage model of coal containing gas is established.Considering the effects of stress and gas pressure on permeability,the dynamic evolution model of permeability is established.Based on the establishment of fluid-solid coupling model around the roadway,using COMSOL software to simulate the gas drainage width of roadway of BaoYu Shan coal seam.The relieved pressure width of the roadway is verified by the method of drilling cuttings,and The accuracy of the model is verified by the gas content method.The results show that: the main influencing factors of relieved pressure are buried depth,support stress,roadway size,strength of coal body.The depth of burial depth is deeper,the sampling depth should be longer and the depth of sampling should be increased in large section roadway and the depth of the sample should be increased with the decrease of support stress.Through the numerical simulation of the roadway of BaoYu Shan coal seam,the gas drainage width of roadway is thirteen meters,which coincides with the facts by proving.The main influence factors of the gas drainage width of roadway are support stress,initial gas content,buried depth and roadway size.What's more,the burial depth,initial gas content and supporting stress show a negative correlation with the gas drainage width of roadway and the road size is positively correlated with the gas drainage width of roadway.