The seepage safety and sliding stability of a clay-core rockfill dam in Africa were examined through a combination of in-situ testing and numerical simulations under various working conditions.The findings indicate that

compared to conventional geological surveys and laboratory test data

in-situ parameters obtained from field direct shear and permeability tests provide greater accuracy and reliability.A multi-source data fusion numerical model based on the in-situ permeability coefficient and on-site monitoring data was established

demonstrating its capability to reflect the seepage behavior of the dam and confirming that no seepage failure occurs under steady-state conditions.The calculated safety factors for sliding stability meet regulatory requirements across all conditions

and the introduction of a safety coefficient

allows for the quantification of the dam’s sliding stability margin.The proposed integrated analysis paradigm combines in-situ testing

multi-source data fusion

and numerical simulation and has enhanced the precision of safety assessments.