Seepage Property of Coal Containing Gas Under Different Paths in Laboratory

According to experimental investigation on seepage property of coal containing gas,the change rule of permeability of coal containing gas is analyzed systematically under different stress paths.The quantitative and qualitative relations between the permeability of coal containing gas and ax-ial pressure,confining pressure and gas pressure were established respectively.The controlling mecha-nism and changing law of permeability of coal containing gas under different stress paths are discussed.The results showed that stress path has an important impact on the permeability of coal containing gas,and the details are: 1) The permeability of coal containing gas decreases with increasing of axial pres-sure and confining pressure,and increases with increasing of gas pressure.2) The relationship between permeability of coal containing gas and axial pressure,confining pressure and gas pressure obeys ap-proximately an exponential law.3) During the whole stress-strain process under the condition of triaxial compression,the change trend of permeability of coal containing gas versus strain curve displays nearly a shape of letter V.The permeability of coal sample decreases with strain first,then increases,and reaches its maximum finally.The rate of permeability at increasing stage is less mildly than that at de-creasing stage.