Experimental study of thermo-fluid-solid coupling seepage of coal containing gas

Abstract：Focusing on anthracites of No.3 coal seam of Zhaozhuang Mine,Jincheng Coal Mining Group,by using self-made ＂thermo-fluid-solid coupling with triaxial servo-controlled seepage equipment of containing-gas coal＂,an experimental study was carried out to investigate the gas seepage law of containing-gas coal during the complete stress-strain process with thermo-fluid-solid coupling,under the conditions of constant gas pressure and confining pressure.The research results show that：with the increase of temperature at coal,the triaxial compressive strength of coal decreases,and the ability of coal to support the deformation of coal decreases,but the elastic ratio of coal increases;the permeability of coal generally experiences a decreasing trend throughout the complete stress-strain process;the small permeability of coal is not conducive to gas drainage before mining,resulting in a large gas pressure gradient between deep coal seams and the coal face,and due to the permeability of high-temperature coal increasing faster in the yield phase,the risk of coal and gas outburst increasing.The relation between coal permeability and stress is not monotonic.The permeability of coal does not always decrease with the increasing of stress,but rather depends on which kind of stress-strain state the coal is in.