The dilatancy and propagation of cracks under compression and shearing are essential to hydromechanical behavior of fractured rock masses. To explore the influence of dilatancy and crack propagation on seepage flow

a new shear constitutive model is developed to describe the features of the pre- and post-shear curves based on residual strength of rocks. Then

by combining the relationship between shear deformation and fracture aperture

a coupled stress-seepage model for fractured rock mass subject to shear dilation process is derived by the minimum potential energy principle and cubic law. In addition

a formulation for determining fracture aperture during crack growth process is obtained by assuming the initiation of mode-I cracks under compression-shear conditions. This model can not only consider shear dilation of rocks

but also imply the effect of crack propagation on the evolution of seepage flow. It is found that the newly developed shear constitutive model is suitable for shear displacement curves with different rough surfaces. A stress dependent seepage model is established by applying the shear constitutive model and is validated by existing coupled shear-flow tests

which is capable of predicting the changes in hydraulic properties of fractured rock masses under compression-shear stress conditions. It is noticed that the stress-seepage model is reliable to reflect hydromechanical behavior of crack propagation by applying the equivalent fracture to the representative of different fractures.