Analysis of deformation and leakage performance of Xiluodu reservoir dam foundation using a coupled two-factor stress-deformation-seepage model

The data for the 285.5 m high Xiluodu reservoir arch dam, China's second-largest, from 2012 to 2021 was monitored and analyzed to assess river valley contraction deformation and dam foundation leaks. The in situ stress had a significant impact on the fractured rock mass deformation characteristics, and the deformation had a strong influence on the rock mass permeability and its seepage behavior characteristics. A deterministic coupling relationship between dam foundation seepage, stress, and river valley deformation was developed. The stress–deformation behavior was consistent with the Kelvin model of the elastic–plastic deformation of rock masses, and the relationship between seepage and deformation obeyed Darcy's law. The proposed coupled two-factor relationships were useful for predicting river valley contraction. The developed models successfully computed the valley contractions associated with deformation and dam foundation leaks with R2 values >0.98 between the modeled results and measured data. This study offers value in the prediction of upstream and downstream river valley contractions after impoundment and can be used as a tool in proposing control measures to alleviate future anticipated problems. •The stress–deformation–seepage response mechanism of the Xiluoudu reservoir foundation during impoundment was investigated.•Three two-factor reliable stress–deformation–seepage coupled models were developed and validated with a field investigation.•The final river valley contraction for the Xiloudu reservoir was predicted to be 78.4 mm using the proposed models.