Simplified Model to Predict Features of Soil-Water Retention Curve Accounting for Stress State Conditions

Stress state is a significant factor influencing the features of the soil-water retention curve (SWRC) under realistic in-situ conditions. The SWRC under different stress state conditions can be evaluated through experimental procedures and various constitutive models. Often, these models require experimental SWRC observations for at least two stress state conditions (i.e., a minimum of two reference SWRCs) to calibrate model parameters, which is difficult owing to the high time consumption associated with such experiments. In the present study, a simplified model is proposed by considering experimental SWRC observations for the single stress state condition to predict SWRC features for other stress state conditions in the gravimetric plane. An attempt has been made to extend the proposed model in the degree of the saturation plane using certain void ratio constitutive relations. The proposed model was validated against several SWRC experimental data sets available in the literature. Good agreement was found between the predicted and measured experimental results in the literature, with wide variations in the type of soils, stress conditions, and sample preparation methodologies. The proposed model is also capable of capturing the variation in key SWRC parameters considering the way the quantity of water is defined. The proposed method is quite simple and hence can be widely used for engineering applications.