Experimental Study of the Water Retention Curve as a Function of Void Ratio

This article presents an experimental study of the water retention curve involving the measurement of void ratio on a drying path. Tests were conducted to determine the variations of water content w and void ratio e induced by variations of the suction s. This study concerns the whole hydric domain of the soil from saturation to dry state. To determine the water retention curve, we used a pressure cell for low suctions and a vapor equilibrium technique (salt solutions) for high suctions. This water retention curve is based on the constitutive relation between water content and suction, for a given void ratio. From saturation, this curve was investigated for different initial states due to different conditions of soil compaction. The results lead to the plotting of a characteristic surface w=w(s,e) which expresses water content as a function of suction and void ratio. It can be considered as a generalization of the classical retention curve. Moreover, this curve can be represented using the degree of saturation as function of suction and void ratio.