Modeling Erodibility of Cohesive Soils Based on Rotating Surface Erosion Tests

Abstract

Surface erosion, which removes the surficial soil grains from the streambeds, slopes, and earthen embankments, is one of the major causes of geohazards and engineering failures. At present, there is no acceptable model that directly predicts the erodibility of cohesive soils subjected to surface erosion. This study proposes a new surface erosion erodibility model for cohesive soils (i.e., sand–clay mixtures), established based on the experimental test results in a purpose-built rotating surface erosion apparatus (RSEA). The proposed model integrates the erosion processes of debonding, rolling, and transportation of soil particles. It enables the correlation of critical hydraulic shear stress to basic geotechnical soil properties and debonding strain energy determined from direct shear tests under zero normal stress. To validate the proposed model, an independent set of experiments was performed. It was found that the proposed erosion model could well predict the soil erosion rate and critical hydraulic shear stress as compared with the measured model.