Coupled model of gas-solid in coal seams based on dynamic process of pressure relief and gas drainage

On the basis of seepage theory of gas flow in coal seams,elastic theory of coal deformation,together with the coupling relationship between gas permeability and porosity,a mathematical model for coupled gas-solid in coal collieries is established.By using the gas-solid coupled model,the mining induced pressure relief,the gas pressure changes,gas drainage and the associated characteristics of gas permeability and gas pressure in coal seam during mining were numerically simulated.The numerical simulation is helpful for understanding the gas drainage mechanisms and for taking effective measures to prevent the occurrences of gas outbursts in collieries.