The accident of coal methane gas is always to threaten the safety in coal production.Researching the interaction law between coal and gas can prevent occurrance of accident effectively.Considering compressibility

adsorption and desorption of gas

and supposing that the gas flow in pore of coal follows Darcy low

we built up a gas-solid coupling mathematical model with consideration of blasting factors.Results solved by comsol show that coal is easily destroyed by blasting excavation than machnical excavation;contrasting to stress coupling blasting load action

coal stresses and displacements is large and coupling effects should not be neglected in mechancal mining;gas pressure changes with time increase of coal rake exposure and has a decrease trend near tunnel

it looks like a funnel distribution;the contour of displacement on top of the tunnel assumes an "O" type distribution and the maximum displacement is the centre of the "O" type distribution.