The water retention curve expressed in terms of water content or degree of saturation and suction is hysteretic, stress path dependent (on void ratio), and depends on pore network. To properly describe its evolving nature, a multimodal retention model is proposed by considering a linear superposition of two subcurves of the Van Genuchten type. The model is constructed based on PSDs obtained with Mercury Intrusion Porosimetry (MIP) data at specified initial state, and thus, is representative of this initial pore network configuration. Based on the WRC model proposed above, the evolution of parameter ¿ will be evaluated based on the microstructural evolution of the pore network. The model is validated based on a series of oedometer samples performed at constant water content and then saturated at different initial void ratio and the same water content.