Research on Tri-axial Compressive Strength of Gassy Coal Under Gas Pressure

The destruction behavior of gassy coal-rock is analyzed from the perspective of coal mass strength,compressive strength of gassy coal-rock considered gas pressure is analyzed by the experiments.The research result shows that lateral pressure effects on failure mode of gassy coal in three-dimensional stress state;residual deformation of gassy coal is related to experimental lateral pressure and coal strength;the greater of the gassy coal strength is,the smaller of the residual deformation is;the elastic modulus of coal increases with the increasing of lateral pressure within the experimental lateral pressure.Both of the compressive strength and elastic modulus decrease compared with uniaxial compression because of the loose gassy coal in the stage of preparation and the effect of gas pressure.The gas has a great effect on strength of coal.Coal strength decreases when it adsorbs gas,and it enhances when gas is released from coal.