A new damage model accounting the effect of joint orientation for the jointed rock mass

Abstract

Damage accumulation in the rock mass leading to failure is influenced by the properties of pre-existing discontinuities. In order to simulate rock mass behaviour realistically, many damage models have been proposed. Amongst them, limited damage models consider joint orientation, one of the significant properties of discontinuities impacting the rock mass failure, in the strongly anisotropic rock masses. In this study, we propose a statistical damage model using the Weibull distribution which takes into account joint orientation by incorporating the Jaeger’s and modified Hoek-Brown failure criteria for jointed rock masses. The proposed statistical damage model is validated using experimental results. Furthermore, verification of the proposed model is conducted by distinct element method using Particle Flow Code (PFC). To investigate the influence of the shape parameter (m) and scale parameter (F0) of the Weibull distribution on the statistical damage model predictions, a sensitivity analysis is carried out. It is found that the parameter m only depends on strain parameter k. On the other hand, the parameter F0 is indirectly related to the failure strength of the jointed rock mass in the proposed damage model. Considerable influence of joint stiffness on the damage variable D, damage evolution rate Dr and rock mass responses are also identified.