Numerical modelling of long-term stability of the rock joint

This paper is focused on the numerical modelling of long-term stability of the rock joint, which has been performed using the extended finite element method. An elastoplastic damage model is developed for the rock matrix around the joints, while a specially developed interface model has been used for the joints. The proposed model for rock joint is based on the assumptions made on the aperture scale. The simplest exponential degradation law has been proposed for both the residual friction angle and the aperture erosion, for taking into consideration the time effects. The proposed model is then used to simulate some direct shear tests realised on the intact and eroded rock interfaces. Comparison of available test results shows that the proposed model is capable to predict satisfactorily the time-dependant degradation caused by either the residual friction angle decrease and/or interface roughness erosion. Therefore, the time effects is numerically analysed via a parametric study on an academic example. The numerical results show that the degradation caused by the decrease in residual friction angle and erosion on the joint surface reduce dramatically joint's resistance.