Influence of Effective Stress on Seepage Characteristics of Coal Under Thermal Stress

In order to investigate the influence of effective stress on permeability of the coal based on thermal stress, seepage tests of triaxial loading under different stress states, different gas pressure and different temperature conditions were carried out by the self-made “thermo-fluid-solid coupling with triaxial-servo controlled seepage equipment system of coal and rock”. The results show that: under three kinds of stress states, the coal permeability decreased with the increasing of temperature. But the decreasing rate of permeability reduced gradually with the increasing of temperature; the crack growth of coal and rock was inhibited by the confining pressure and axial pressure, so that the rate of permeability decreased gradually; according to the relationship between permeability and effective stress under the thermal stress, the calculation results are in good agreement with the experimental results, which can well reflect the permeability of coal samples.