Modeling the shearing behavior of discontinuous rock mass incorporating dilation of joint aperture

Abstract

The shearing characteristics of rock joints govern the mechanical performance of discontinuous rock masses. The present study investigated the normal compression and shear behavior of rock joints through cyclic compression tests and direct shear tests. The irreversible relationship between the normal stress and the normal closure was confirmed by cyclic compression tests on rock joints. An elastoplastic model was proposed incorporating the aperture variation. A modified version of the critical state framework was developed for modeling the shearing and dilation behavior. Specifically, the initial state of the rock joints was determined according to the stress history. The proposed model for the mechanical behavior of rock joints was validated by predicting the experimental results. A parameter analysis was also performed to highlight the difference in the shear behavior of the rock joints due to the difference in the initial apertures.