A New Constitutive Model for Rick Joint and Its Numerical Implementation

The mechanical property of rock discontinuities is one of controlling factors of deformation, strength and stability of rock mass. Due to the limitation of available constitutive models for rock discontinuities within the framework of classical continuum mechanics, a new constitutive model for rock discontinuities is presented by taking use of the direct methodology based on the strength and deformation behaviors of rock discontinuities. In the presented model, the tangential stress and deformation curve and dilation curve are divided into linear part before peak point, nonlinear part before peak point, and softening part after peak point, and the mathematical models which can accurately characterize the major mechanical behaviors of rock dis-continuities are given. Based on the above-mentioned, the incremental constitutive model for rock discontinuities is developed. Then, a classical direct shear test of rock discontinuities are simulated by the developed model in this paper and the Plesha's model which is used widely, and the results show that the major mechanical behaviors of rock discontinuities can be reasonably described by the presented model, and the simulation ability of the presented model is better than the Plesha's model. In the last, through the combination of the proposed model and the joint element method, a new joint element is developed by using the user element subroutine interface UEL in ABAQUS. The correctness of the development of the subroutine is validated by a numerical test.