Egg-shaped elasto-plastic constitutive modeling for over-consolidated clay

An elasto-plastic constitutive model suitable for over-consolidated clay was established within the framework of egg-shaped function, to describe the strength and deformation characteristics of over-consolidated soft clay under different stress conditions. Firstly, the development of plastic strain (dilatancy or contraction) for clay under over-consolidation state was analyzed according to the test results from a series of stress path triaxial compression test. Meanwhile, the previously proposed rotational plastic potential flow rule was developed to meet the plastic deformation characteristics of over-consolidated soils by introducing the peak stress ratio and constructing approximate linear dependence between the normalized plastic potential rotational angle and the stress state parameter under dilatancy. Then the egg-shaped elasto-plastic constitutive model for over-consolidated clay was be well established by introducing a generalized plastic work hardening principle in which the equivalent hardening parameter was employed. Finally, the validity of this model was demonstrated by comparison between test data and model prediction of triaxial compression test. Results show that the proposed model can effectively reflect the stress-strain characteristics of over-consolidated clay under different loading conditions, such as softening and dilatancy. © 2021, Zhejiang University Press. All right reserved.