Experiment on Permeability Properties of Coal Samples With Low Permeability in Complete Stress-strain Process

Permeable experiments on complete stress-strain process of coal samples were carried out with MTS815.02 rock servo test system.The complete stress-strain curves under different confining pressures were obtained.Then,the geometric features of permeability-strain curves of coal samples in complete stress-strain process were discussed.The relation between axial stress and permeability of coal samples during the course of deformation and failure was studied.The effects of confining pressure on the permeability of coal samples were also analyzed.The results showed that the effects of axial stress on Darcy flow permeability properties and non-Darcy flow permeability properties were synchronous.The peak value of permeability of coal samples lagged behind the peak value of the stress-strain.As the confining pressure increased,the permeability of coal samples presented the downward trend in general.