Study of Shear Constitutive Model for Schistose Rock Mass

Based on the direct shear tests of schist and shale at dry and water-saturated states, combed with the advantages and disadvantages of models for rock mass and structure surface, we proposed shear stress-displacement constitutive model of schistose rock mass. The model is in the form of piecewise exponential function and its advantages are as follows: Piecewise function can reasonably describe the nonlinear pre-peak shear hardening and post-peak shear softening characteristics; Regard peak strength, peak displacement and residual strength as critical points, so it can accurately describe the strength characteristics of the material; The fitting degree is high with direct shear tests both at dry and water-saturated states; Only one parameter value is needed to obtain by fitting experimental curves while others are convenient to determine. All of those are benefit to applications in engineering practice.