Double Potential Surfaces Constitutive Model of Unsaturated Soil

The mechanical property of unsaturated soil becomes complex because of the matric suction. Using water content or saturation replace matric suction may be an effective method. Based on the generalized potential theory, the traditional field surface is replaced by the plastic state equations. The unsaturated property was reflected approximately by plastic parameters with initial saturation. A double potential surfaces constitutive model of unsaturated soil was built. Linear function and quadratic function were used in model parameter fitting. It was shown that the model was based on mathematical law, suction measurement was avoided. The unsaturated soil deformation properties with initial saturation were reflected in the model, which shows that the model is practical.