Seepage rules of loaded coal containing gas under the coupling effect of temperature and axial deformation

Using the self-made triaxial seepage experimental device, an experiment was carried out under the condition of constant confining pressure, gas pressure and different temperatures, to simulate the gas seepage process of raw coal containing gas during the coal body deformation, and build the qualitative and quantitative relations between the permeability of loaded coal containing gas and temperature or axial strain. The results show that: 1) Axial strain has a great impact on loaded coal containing gas. Before the yield step of loaded coal containing gas, the permeability has decreased with the increment of axial strain, and the decreasing extent decreased gradually. After the unstable failure, loaded coal containing gas was broken suddenly, resulting in the permeability increasing severely to 769%. 2) Effect of temperature variation on permeability is closely associated with the stress-strain stage of coal containing gas. The experiment demonstrates that the influence of mining process on permeability of coal containing-gas can be divided into three main phases, that is, matrix expanding outward, matrix expanding inward, and slippage effect. 3) Calculation formula about the permeability of loaded coal containing gas was built suitable for the common effect of deformation and temperature, that is, k=(aT+b)εcT+d. This formula can well describe the relationship between the permeability of loaded coal containing gas and the deformation and temperature. The results can provide theoretical basis for the reveal of gas seepage law and mine gas prevention and control. ©, 2015, China University of Mining and Technology. All right reserved.