Modelling rockbursts around a deep tunnel based on the particle finite element method: From progressive degradation to catastrophic ejection

We develop a novel computational framework based on the particle finite element method for simulating rockburst phenomena, from pre-failure initiation to failure evolution and to post-failure mobilisation and ejection, across spatiotemporal scales in hard rocks. The proposed framework builds upon a rigorously validated and extensively calibrated particle finite element model, distinguished by its unique capability to handle large deformation problems. This framework can simultaneously capture the creep damage mechanism based on a time-dependent strength degradation model and the brittle fracturing process based on a cohesion loss-frictional strengthening model. The post-failure mobilisation is further governed by a frictional weakening formulation to capture the associated stress drop behaviour. We consider the intrinsic material heterogeneity assuming a Weibull distribution of rock mass properties and represent the nearby fault zone as a thin continuum layer with equivalent mechanical properties. We apply the model to investigate the processes and phenomena of deep tunnelling-induced rockbursts under different stress and heterogeneity conditions. Our simulation results, grounded in a thoroughly validated modelling framework, yield insights with important implications for understanding and predicting catastrophic rockbursts during deep tunnel excavation. While further site-specific calibration would be required for practical application, the current framework demonstrates strong potential as a predictive tool for evaluating rockburst hazards in complex geological settings.