关键词: 热力学, 塑性剪切自由能, 超固结土, 本构模型

Abstract: The free energy and dissipation function for over consolidated clays are established, which are based on the generalized thermodynamic method and combined with the thermodynamic functions form of the modified Cam model. The energy generated by the plastic shear deformation is considered a part of free energy in the free energy function, and this partial free energy is related to the degree of over consolidation. When the degree of over consolidation decreases, the free energy generated by the plastic shear deformation also decreases. The dissipation function is independent of the current stress state, so the associated flow rule is still employed in this paper. Based on the free energy function and the dissipation function, all of the yield function, the flow law, the hardening law and the elastic law can be obtained with strict mathematical derivation from the two scalar functions. The final elastic-plastic incremental relation can then be obtained. Finally, the rationality of the model is verified by comparing the calculation and experimental results in stress and strain, volumetric strain of four different over consolidation clays.

Key words: thermo mechanics, plastic shear free energy, over consolidation, constitutive model