MODELING ROCK JOINTS UNDER SHEAR AND NORMAL LOADING

A model is presented to determine the effect of boundary conditions on the shear behaviour of a dilatant rock joint. The model is given in both graphical and mathematical forms. It relates the normal load-deformation response of a joint to its shear load-deformation and dilatant behaviour. The proposed model predicts the increase in normal deformability of an initially mated joint as it traverses a range of unmated conditions. It provides a tangent formulation for the deformability of a rock joint that fully accounts for the coupling between joint normal and shear response due to dilatancy. Finally, the applicability of the proposed model to predict the behaviour of a rock joint under applied constant normal stiffness boundary conditions is verified using existing experimental results.