The model of water retention curve considering effects of void ratio

Abstract

Water retention curves derived from some initial conditions based on experimental results and some factors affecting the water retention curves are examined. On the drying process of the water retention curve, degree of saturation, water content and void ratio tend to converge to a specific value with increase in suction. And, the value can be regarded as a constant in terms of the water content. The suction value at which the desaturation begins on the drying process from the saturated state is called “Air Entry Value” and depends on the void ratio. The relationship between the air entry value and void ratio can be described as a unique “Air Entry Value Line”. On the wetting process, it is found that the shape of the water retention curve depends on the degree of saturation. Likewise, the water entry value on the wetting process can be expressed as a function of void ratio as the “Water Entry Value Line”. Thus, in this paper, a new model for the water retention curve adopting the concept of “Virgin Drying Line” presented by Toll is proposed. It is shown that the model can predict the hysteresis loop in the water retention curves when the initial states (suction, void ratio, water content) of specimen are provided.

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