A GENERALIZED CUBIC LAW FOR ROCK JOINTS CONSIDERING POST-PEAK MECHANICAL EFFECTS

摘要

A joint deformation model and a generalized cubic law are proposed to model the mechanical and hydraulic behaviours of rock joints subjected to normal and shear loading. The deformation model is established in the framework of non-associative elastic-plasticity, with special emphasis on modelling the coupling effect of post-peak dilatancy and shear softening. The generalized cubic law is proposed on the basis of the deformation model by taking into account evolution of joint contact area ratio and by virtue of the equivalence principle of flow dissipation energy. Experimental validations show that the proposed model has better capability to predict the hydraulic property of real hard joints, especially in modelling the irreducible flow behaviour of the joints under significant normal closure and in modelling the post-peak flow behaviour with remarkable shear dilatancy.