This study aims to evaluate the internal erosion sensitivity of dam core soil of Minjiang navi- gation and hydropower hub project under controlled seepage conditions. The geotechnical properties and dispersibility of soil are analyzed through laboratory tests to reveal the erosion vulnerability mechanism. Based on the measurement results and engineering guidelines

the soil is classified and the erosion sensi- tivity is evaluated. The test results show that the sample size significantly affects the erosion parameters

and there are significant differences between different units. Although the erosion coefficient values vary by test units

according to the engineering criteria

the three types of soil erosion categories are generally similar. It is worth noting that the soil with lower clay content exhibits stronger resistance to internal ero - sion. This study provides important foundation for understanding the internal erosion sensitivity of dam core soil

and reveals the key effects of sample size and clay content on the erosion process.