Acoustic emission source localization in complex rock structures using sparse-grid fast path tracing method

Accurate localization of acoustic emission (AE) sources is critical for identifying precursor information of rock failure. However, achieving high localization accuracy in complex rock structures remains challenging. This study presents a novel three-dimensional AE source localization method suitable for rock masses with underground caverns. The proposed approach integrates a sparse-grid octree structure with a line-of-sight-based path optimization algorithm, effectively addressing path tracing errors caused by geometry-grid misalignment and narrow geological features through localized mesh refinement. Synthetic tests using a room-and-pillar model indicate that the method significantly improves wave path tracing accuracy and localization precision compared to the improved A∗ algorithm, while reducing computational cost by 98 %. Field application in a mine with extensive caverns confirms that the method effectively resolves mislocalization issues inherent in the straight-path method, yielding microseismic event locations consistent with observed collapse zones, while maintaining high accuracy even with fewer sensors. These results demonstrate the robustness, efficiency, and practical value of the proposed method for source localization in complex rock engineering environments.