Rockburst evolution modeling with fracture-ejection behavior by a quasi-state-based peridynamics with cluster motion algorithm and energy-based criterion

Rockburst is a dynamic hazard with sudden occurrence and rapid energy release involving fracture localization and violent ejection of fragmented rock blocks during tunneling under high-stress environments. However, numerical simulations of rockbursts still lack a cluster-scale description of post-detachment rock block dynamics and an objective criterion for identifying whether the simulated motion constitutes a rockburst event. To address these gaps, a unified numerical framework integrating quasi-state-based peridynamics (QSBPD) with a motion-collision-fragment algorithm is developed for rockburst numerical modeling. This algorithm allows the post-failure rock block response, including separation, translation, rotation, collision, and secondary fragmentation, to be tracked in a unified manner, rather than being treated implicitly or omitted. Furthermore, an energy-based dual-index criterion is introduced to reduce ambiguity in event identification by distinguishing strain energy-driven ejection from gravity-dominated rock block motion and quantifying the strain-to-kinetic energy conversion. The proposed framework is evaluated using the Jinping 11·28 rockburst case. The simulation result reproduces the four-stage evolution, localized V-shaped failure zone, cluster ejection and interaction, and fragmentation observed in the documented event. The cluster velocities exhibit a clear size dependence, with smaller clusters moving faster than larger ones. Energy analysis identifies a pronounced conversion during the burst episode, with a global strain-to-kinetic energy conversion ratio of 44%. This energy signature provides a quantitative basis for identifying the simulated event as a rockburst and supports the applicability of the proposed energy-based criterion. The proposed framework provides a physically interpretable tool for process-consistent rockburst simulation and quantitative energy assessment.