A Unified Computational Framework for Modelling Rock Failure Evolution: From Progressive Degradation to Catastrophic Rupture and Avalanche

ABSTRACT: In this study, we develop a novel unified computational framework for modelling the evolutionary behaviour of fractured rocks from progressive damage to catastrophic rupture and runout. In this framework, physical laws are coupled with failure criteria to describe the combined effects of time-dependent degradation and strain-driven processes; heterogeneities are considered by the representation of pre-existing fractures and statistical distribution of elasticity in rocks; an implicit time integration scheme is adopted to capture the deformational behaviour across multiple time scales; the particle finite element technique is applied to track the large deformation of rock masses. We demonstrate this computational framework for investigating rock failure evolution in both natural settings and engineering configurations, i.e. weathering-induced rock slope failures and tunnelling-induced rockbursts. We show that the model can realistically capture the complex responses of fractured rocks prior to failure, diverse rupture patterns during the failure, and various mass movement dynamics after the failure. Numerical simulations also indicate the strong control of geological heterogeneities on rock failure evolution. This unified computational framework can serve as a robust and powerful tool to unravel the origin of catastrophic rock failures, assess the risks related to potential extreme geohazards, and develop physics-based early warning systems in practice. 1. INTRODUCTION The entire history of rock mass failure involves long-term destabilisation processes (Amitrano & Helmstetter, 2006), the formation of ‘system-sized’ fractures (Main, 2000), and the avalanche of failed materials, which are strongly coupled over the space and time domains. More specifically, destabilisation processes could lead to various failure patterns and dynamics, which may further affect the post-failure runout characteristics (L. Wang & Lei, 2023). Therefore, understanding the evolutionary behaviour of geomaterials across multiple time and length scales is of central importance for predicting the timing and magnitude of failure events (Ö. Aydan et al., 1996; Eberhardt, 2008). However, the involved material and geometric nonlinearities have posed a great challenge to developing numerical models for rock mass failures.