Discussion of ''A new modelling approach for unsaturated soils using independent stress

The authors intended to develop a critical-state elastoplastic model for unsaturated soils with a smooth transition from saturated to unsaturated conditions for soils prepared from a slurry and from compacted specimens, which is an important topic that remains unsolved. The discussers would like to share some perspectives on the implications of the paper and ask for clarifications on presentations in the paper. Modelling of the volumetric behavior Modelling of soil behavior in the elastic zone Equation [9] was adopted in the paper for the elastic (recoverable) volume change caused by stress and suction changes. When the suction is less than the saturation suction (s ssa). Since points A and D and stress paths ABD, ACD, and AED are in the elastic zone, the loading process should be stress-path independent according to the theory of elastoplasticity. That is, if we start from point A and take stress path ABD, ACD, or AED, the final specific volume for point D should be the same (or, if we start from point A and follow stress path ACDBA, there should be no volume change, since the whole stress path is in the elastic zone). To satisfy this requirement of stress-path independency, the following relationship should hold according to Green’s theorem: