Hysteretic Water-Retention Behavior of Bentonites

Abstract

Understanding the hysteresis in the soil water characteristics of bentonites is important for predicting the hydraulic and mechanical response for many geotechnical applications. The initial drying and main wetting soil water characteristic data of four bentonites were established by using different suction control/measurement techniques to investigate the hysteretic behavior. The wetting data were established by maintaining the initial condition of the specimen to be at the residual state of the drying curve, which paved the transition from drying to wetting path. The influence of bentonite plasticity on the wetting and drying soil water characteristic curves (SWCCs) was analyzed. A theoretical model was proposed for predicting the boundary wetting SWCC from the initial drying SWCC data and two additional data points along the wetting path. The validation of the proposed model showed that the predicted boundary wetting curve was in very good agreement with the measured data and fitted boundary wetting curves for all the bentonites. The model further accurately predicted the main wetting curves of different clay soils from the literature, indicating its potential application for predicting the hysteretic behavior of clay soils in the absence of measurements over a wide suction range.