Solid-gas coupling dynamic model and numerical simulation of coal containing gas

An effective stress calculation formula for coal containing gas is proposed coupling with the swelling stress of gas adsorption in the effective stress principle for porous media.Considering the variation of the porosity and permeability of coal containing gas at differential deformation stages,a dynamic model for porosity and permeability is developed based on the previous research results.Furthermore,taking coal containing gas as a kind of isotropic elastoplastic material and taking into account the effect of gas adsorption,the stress and seepage equations are derived and,the solid-gas coupling model for coal containing gas is constructed,which is appropriate to describe the skeleton deformability of coal containing gas and the compressibility of gas under the solid-gas interaction condition.In addition,the numerical simulation model is built by using the finite element method,and the numerical solution of the model for a special loading case is given in term of the constraint conditions and corresponding parameters.The research results maybe have a meaning for further enriching and improving solid-gas coupling theories for coal containing gas.