Dynamic acoustic emission source localization and damage evolution analysis of rock under compressive loading

Understanding the dynamic damage evolution of rock is crucial for ensuring underground engineering stability. However, traditional acoustic emission (AE) source localization methods that rely on pre-measured velocity models introduce significant errors under heterogeneous media evolution. This study uses a self-developed AE monitoring system to investigate dynamic AE source localization and damage evolution in rock subjected to compressive loading. AE sensors captured spatiotemporal acoustic signals while velocity field inversion was performed by traveltime tomography to track crack propagation across four loading stages: crack closure, elastic deformation, stable crack propagation, and unstable crack propagation. Results, as visualized in Section 4, demonstrate that the velocity field increases dominantly during the initial stages, then exhibits localized attenuation as damage accumulates. A velocity-free localization method simultaneously solves for event locations and effective velocities, eliminates dependence on pre-measured velocity models, and achieves high-precision AE localization. The deduced localization results align with the X-shaped shear failure pattern of the specimen. This combined localization and tomography approach provides a reliable tool for real-time characterization of rock damage evolution, advancing fracture mechanism analysis and engineering monitoring under complex conditions.