Modelling the pre- and post-failure behaviour of faulted rock slopes based on the particle finite element method with a damage mechanics model

Abstract

We develop a novel numerical model incorporating a damage mechanics formulation into the particle finite element method for analysing the pre- and post-failure behaviour of faulted rock slopes. In this computational framework, the stress-driven strain localisation and damage evolution are modelled based on an isotropic damage model; discontinuity structures like fault zones are represented as thin continuum layers with equivalent mechanical properties; the particle finite element method is used to solve and track the large deformation of rock masses. In the paper, we first present the mathematical formulation of the proposed model in the context of the Hellinger-Reissner variational principle. We conduct a thorough validation of our model for simulating the damage of brittle materials against well-documented experimental datasets of different failure scenarios. We then apply the model to simulate the deformation and failure phenomena of faulted rock slopes including both the pre-failure progressive damage and post-failure transient runout, demonstrating the strong capability of our model in physically capturing the initiation, evolution, and consequence of catastrophic rock slope failure across multiple temporal scales. In addition, our simulations can realistically reproduce the slope displacement time series with the interplay between rock damage and fault reactivation explored. The present work has important implications for understanding the physical mechanisms that drive the progressive destabilisation and catastrophic failure phenomena of rock slopes in nature.