Pre-peak shear constitutive model considering the softening shear stiffness and its influencing factors

The shear stress-displacement curve is an important tool in the study of the shear behavior of rock joint. However,at present,most of the shear models characterizing pre-peak shear behavior are linear,which are unable to describe the nonlinear characteristics well. The existing nonlinear description is only the phenomenological description, which fails to reflect the physical meaning and clarify the important parameters affecting the model. Based on the nor-malized idea,it is convenient to non-dimensionalize the shear stiffness and displacement,and the relationship between the shear stiffness and the displacement is represented by the hyperbolic function. The pre-peak shear constitutive model considering the softening shear stiffness is proposed,and verified by experimental results. The initial shear stiff-ness and the peak shear displacement are the main factors affecting the pre-peak shear constitutive model. The influen-cing factors of initial shear stiffness and the peak shear displacement are discussed,which is useful for further clarif-ying the mechanism of the pre-peak shear behavior.