Abstract: Comparing to the other critical state model, the thermodynamics-based critical state (TCS) model can meet principle of the thermodynamics without introduction of plastic potential function. This model can be used to model the influence of K0 consolidation by modification of it. The return-mapping algorithm is utilized to conduct the redevelopment of TCS model in ABAQUS. The certification of this model can be given by the comparison with modified Cam-Clay (MCC) model offered by ABAQUS. Otherwise, the variation of the yield surface shape controlled by two parameters is discussed. The influence of these two parameters on the stress-strain relationship and dilatancy is also analyzed. The modification of parameter in TCS model can be used to describe non-ellipse yield surface extending available range of TCS model. Different parameters have different influences on the shape and size of yield surface. Meanwhile, it is shown that the stress-strain relationship and dilatancy are different between described by TCS model where the K0 consolidation and stress rotational hardening are considered and described by MCC model without consideration of them are shown. For the real soils, K0 consolidation and rotational hardening are basic mechanical properties of soils. This paper demonstrates that TCS model can be used to describe these features of soils compared with MCC model where the rotational hardening and K0 consolidation are not considered. So, it is more available.

Key words: critical state, stress-strain relationship, dilatancy, yield surface, thermodynamics