Coupling analysis of seepage and stress-strain of rock fracture during shear process

Considering the different levels of normal stress, the relationship between shear stress and shear deformation of rock fracture is built firstly. The elastic matrix for rock fracture is improved; and the relationship between the shear deformation and the shear stress is divided into three phases, i.e. shear shrink, shear dilation up to peak value, residual shear strength. Then, applying the composite element algorithm, the coupling mechanism of seepage and stress-strain for rock fracture during shear process is realized, by which the variation and relationship among shear deformation, aperture of rock fracture, conductivity of rock fracture, seepage field as well as stress filed are illustrated. The numerical example indicates that, with constant mechanical parameters of filling medium in the fracture, the flow velocity of fracture keeps constant as well and does not change with variable shear deformation and normal stress, but the discharge per unit width through rock fracture changes because of the change of fracture aperture; while with lower normal stress, the shear deformation has more influences on the fracture aperture and the discharge per unit width through rock fracture.