Research on Confining Pressure Effect in Gassy Coal Failure Process

In order to investigate the effect of confining pressure on mechanical properties of gassy coal in Huaibei Mining Area,the gassy coal is analyzed though triaxial test. The gassy coal's strength, deformation and failure condition under three different confining pressures are simulated by RFPA^2D-Flow. It shows that the ultimate compressive strength, residual strength and elastic modulus of gassy coal are enlarged with increasing confining pressure. The residual deformation of gassy coal is related with confining pressure and the strength of gassy coal itself. The greater the confining pressure, the smaller the residual deformation. Gassy coal softens gradually after elastic deformation stage in loading process. And it shows a certain plastic character when soften decreases. The rupture form of gassy coal also changes with the changing confining pressure. The angle between the macroscopic rupture face of gassy coal and greatest principal stress direction enlarges with the changing confining pressure.