Integrated geophysical and computational modeling of hydromechanical mechanisms of underground debris flows in mining region

Abstract

Underground debris flows, arising from the complex interplay of anthropogenic activities and rainfall-induced hydromechanical processes, present significant geotechnical hazards that remain poorly understood due to their hidden nature and dynamic multiphase triggers. Focusing on underground debris flow in a mining area in Southwest China, this study advances an integrated framework combining air-ground transient electromagnetic method (AGTEM) and computational fluid dynamics coupled with the discrete element method (CFD-DEM), revealing the migration mechanism in which microscale multiphase hydraulic erosion drives the macroscopic initiation of underground debris flow. Key findings include: (1) The identification of three transport phases (rapid erosion, slow erosion, and stabilization) provides actionable thresholds for monitoring and mitigation. (2) The coupled feedback between hydraulic conductivity anisotropy and the formation of preferential flow is the primary driver of large-scale debris transportation. (3) Linking mining-induced seismic energy to vibration-induced liquefaction via DEM simulations offers a physics-based explanation for flow mobilization triggers. The integrated geophysical-numerical framework offers new capabilities for predicting initiation thresholds and developing physics-based mitigation strategies in mining-affected terrains.

Keywords

Underground debris flow / Multiphase hydromechanical coupling / Hydraulic erosion / AGTEM / CFD-DEM

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

CRediT authorship contribution statement

Yu Zhang: Software, Data curation, Methodology, Conceptualization, Writing - original draft, Investigation. Kun He: Validation, Methodology, Writing - review & editing. Xiewen Hu: Funding acquisition, Writing - review & editing, Conceptualization, Supervision. Wenlian Liu: Writing - review & editing. Sugang Sui: Writing - review & editing. Gang Luo: Writing - review & editing. Mei Han: Writing - review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

The authors gratefully acknowledge support from the National Natural Science Foundation of China (Grant Nos. 42377170 and 42407212), the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation (Grant No. GZB20230606), the Postdoctoral Research Foundation of China (Grant No. 2024M752679), and the Sichuan Natural Science Foundation (Grant No. 2025ZNSFSC1205).

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