Experimental Study on Influence of Gas Pressure on Coal Adsorption/Desorption Deformation Characteristics

Based on 8^# coal seam of coal core samples of Yuyang Coal Mine of Songzao Coal and Power Company, the experiments of coal adsorption-desorption deformation were carried out under different gas pressures. The test result indicated that: the adsorption-desorption deformation dynamic curve of coal containing gas could be divided into vacuum compression deformation stage I, adsorption swelling deformation stage II, and desorbed shrinkage deformation stage III; the adsorption-desorption deformation of coal had obvious anisotropic characteristics. The ratios of horizontal and vertical deformation did not change significantly with time and pressure, and it tended to be constant;the volumetric deformation of coal containing gas increased linearly with the increase of adsorption/desorption pressure. At the same time, the longer the adsorption/desorption time, the greater the linear slope; the adsorption-desorption deformation was irreversible. The residual deformation increases with the gas pressure, and the vertical deformation provided more contribution to residual volume deformation.