Mining Field Pressure And Coalbed Gas Seepage Solid-Gas Coupled Study In The Condition Of Composite Key Stratum

With the depth and intensity of exploitation increase, some proximal hard rock appeared composite effect, the resulting rock press appearance has greater challenges to gas drainage in coal seam. So studying hard rock's composite effect and its influence to the rule of coalbed methane seepage's, has great theoretical and engineering significance for guiding gas drainage in coal seam in the condition of composite.The main contents:(1)Using composite material structural mechanics theory, analyzed Composite Key Stratum's force theoretically, detruded Winkler foundation Composite Key Stratum's interval. Using advanced press'pass,spreading and attenuation to deep, which formed by Composite Key Stratum's flexure in its very near under stratum, achieved coal mass advanced press in the condition of Composite Key Stratum structure. Provided theoretical basis for determining working face's cross-off pace and support lectotype in the condition of Composite Key Stratum.(2)Using RFPA3D numerical simulation, contrastively analyzed the interval law,advanced press distribution and coal mass'deformation law of Composite Key Stratum,combination Key Stratum and anti-Composite Key Stratum; Applied physical modeling experiments analyzed and got the law of Composite Key Stratum interval and advanced pressure distribution, effectively revealed the combined effects of Key Stratum.(3)Using coal sample's electro-hydraulic servo test of complete stress-strain process infiltration characteristics, determined coal rocks'gas permeability, and analyzed the impact of stress, strain, pore pressure; Built coal-bed methane seepage coupled mathematical model in the influence of Composite Key Stratum, meanwhile, discussed time variable discretization,representative elementary volume analysis and coal mass formation field equation discretization to coal-bed methane seepage coupled mathematical model.(4)Using RFPA2D numerical simulation, considered the impact of Composite Key Stratum and anti-Composite Key Stratum on the advanced pressure and gas seepage of the coal seam, analyzed the change rule of overlying strata movement,advanced pressure and gas permeability coefficient caused by mining in these two structures.(5)Through the rockburst observation and gas monitoring in 101 fully mechanized top-coal caving face of Ting Nan mine, got coal face waighting distance and coal mass advanced press, which is similar to the results of theoretical calculations of Winkler foundation Composite Key Stratum; analyzed the impact of advanced press and coal mass formation to gas emission, its gas emission law is similar to the results of seepage coupled mathematical model calculations, thus validated the correctness of the thesis'theoretical analysis by field examples; On this basis, carried on optimal designing to coal face methane pre-extraction parameters, has achieved remarkable economic and social benefits.Through composite material structural mechanics theory, built Winkler foundation Composite Key Stratum model in the thesis, analyzed Key Stratum interval and advanced press in front of coal face, based on this, built coal-bed methane seepage coupled model in the influence of Composite Key Stratum, applied research results successfully in 101 fully mechanized top-coal caving face of Ting Nan coal, and carried on optimal designing to methane pre-extraction parameters in 101 fully mechanized top-coal caving face, extraction effect is remarkable, has achieved certain economic and social benefits.