Slope deformation and failure mechanisms at submerged geoarchaeological sites: physical–numerical modeling

Reservoir bank collapse poses severe threats to submerged geoarchaeological heritage. This study investigates slope failure mechanisms at the Jiaopingdu Heritage site in the Wudongde Reservoir inundation zone through integrated physical modeling and FLAC-3D simulation. Results demonstrate that cyclic water-level fluctuations progressively degrade slope stability, with earth pressure decreasing and pore water pressure increasing with each impoundment cycle. Domed cave structures exhibit significantly superior stability compared to flat-roofed configurations during slope destabilization. The research identifies a critical hydromechanical coupling mechanism where interstitial fluid migration governs progressive structural degradation through soil-water interactions. Numerical analysis reveals a low long-term stability coefficient (0.89) and identifies poorly cemented basal gravel layers as the primary control on failure boundaries, providing essential theoretical foundations for predicting bank stability and developing effective in situ conservation strategies for vulnerable underwater cultural heritage sites.