Abstract:Based on the concept of disturbing structure, this paper presents a progressive yield constitutive model by extending the CamClay model in order to describe influence of the disturbing structure on soil behavior. The internal variable of yield surface is not just a constant parameter, and it should be treated as a distribution function in a range. The single yield surface of the CamClay model wis extended to a field of yield surface. Then by introducing the progressive yield concept into the CamClay model, the progressive yield constitutive model wis developed. Only one parameter wis added besides the three parameters of the CamClay, which represents the disturbing structure of the soils. The application results show that the model can predict the progressive yield of the soils.