A reduced-order constitutive model and discretization strategy for shearing behavior of rock joints

Abstract

Rock joints show a significant effect on the mechanical properties of rock masses. The existing constitutive approaches of rock joints focus on the complex shearing behavior while their accuracy still needs to be improved. In this paper, a reduced-order constitutive model of rock joints is proposed, which can accurately describe the shearing behavior in the whole displacement domain and can reduce the degree of freedom of contact interfaces to improve computing efficiency. The model contains five parameters with clear physical definition and can be identified directly through macroscopic experiments. Based on the strategy of evenly divided stiffness, a discretization method of the model is derived. The results show that the model can depict the mechanical behavior of both natural joints and regularly shaped joints, regardless of JRC conditions and normal stresses. When the discretized controlling variable is set as 2.6, the numerical results are in good agreement with the analytical solutions. During the post-peak stage, only 5 Jenkins elements are needed to realize a calculation error of 0.4%.