Experimental Study on Seepage at the Soil-Structure Interface

To investigate the seepage erosion failure mechanism at the interface between earth-rock dams and culverts, this study systematically examined three key factors—clay content, compaction degree, and duration of hydraulic gradient—and their influence on interface stability. Seepage erosion tests were conducted using clay-sand mixed soil in contact with structural interfaces.
Three soil sample types with varying clay contents were prepared, and their specific particle size distributions are detailed in Data 1. By applying different hydraulic gradients, the dynamic flow velocity and mass loss of particles during seepage were recorded. Representative data from three typical experimental conditions are presented in Data 2. Data 3, 4, and 5 respectively illustrate how clay content, compaction degree, and duration of hydraulic gradient affect seepage velocity and hydraulic conductivity. These datasets provide insights into the macroscopic seepage characteristics and the progression of erosion within the interface zone.
To further elucidate the erosion mechanisms at the mesoscopic scale, nuclear magnetic resonance (NMR) technology was employed to monitor pore structure evolution before and after the application of hydraulic gradients. This included changes in pore distribution, porosity, free water, and NMR permeability. The corresponding mesoscopic data are detailed in Data 6 (Sheet 2) and Data 7 (Sheet 3).
Collectively, these datasets capture the multi-scale erosion process, ranging from macroscopic seepage behavior to mesoscopic pore evolution. They not only support the validation of existing seepage erosion models but also serve as a critical foundation for safety assessments and numerical simulations of soil-structure interfaces.