The validation and application of electrical measurement for evaluating soil internal erosion under rainfall condition

Internal erosion is capable of leading to substantial soil losses and piping erosion in prolonged rainfall scenarios and the research about it poses a significant challenge. The current landscape lacks comprehensive insights into evaluating internal erosion at both macro- and micro-scales. To address this gap and quantitatively assess soil erosion, we define the erosion factor as the rates of change of various parameters, encompassing microstructure, soil resistivity, and slope erosion morphology characteristics. An indoor rainfall erosion experiment was meticulously crafted, integrating computed tomography (CT) and electrical measurements. Results unveil the nonlinear dynamics of internal particle losses and fracture generations concerning rainfall intensity. Erosion factors, defined by micro-parameters like fractal dimension and probability entropy, exhibit an exponential correlation with resistivity change rates. Furthermore, a three-dimensional (3D) model test was conducted, employing 3D scanning and electrical measurement. Digital elevation models (DEMs) illustrate the formation of splash pits across the slope and the expansion of erosion rills, particularly in low-lying areas. Two resistivity profiles exhibit similar increasing trends attributed to internal erosion. Classifying erosion states based on erosion factors of macro-deformation parameters and soil resistivity underscores spatiotemporal characteristics, notably downward evolution, maintaining consistency between surface and internal erosion. Subsequently, electrical measurement validated internal erosion induced by infiltration channels in in-situ slopes before and after the rainy season. In conclusion, this study unveils intricate relationships among resistivity, macro- and micro-parameters, highlighting the promising potential of electrical measurements in nuanced internal erosion evaluation.