A model for weakly unsaturated soils taking into account the three phases (air, water and soil)

WM in the following), which is specifically related to the Loading-Collapse (LC) yield curve. A slight modification is then made and a hydro-mechanical coupling constitutive model (MWM after Modified Wheeler’s Model) is established within the Critical State Soil Mechanics. Comparisons between the WM model and the MWM model and also validations with experimental results are conducted.