A unified hardening model for K₀ overconsolidated clays

The constitutive model for overconsolidated clays proposed by the authors was extended to an overconsolidated clay model with stress-induced initial anisotropy.By introducing the potential strength ratio Mf,the characteristic stress ratio M,and state stress ratio ηk into the unified hardening parameter,the proposed model could well simulate many characteristics of overconsolidated clays,including stress-induced initial anisotropy,stress dilatancy,strain hardening and softening,and path dependency behaviour.Based on the SMP criterion and the corresponding transformed stress tensors,the proposed model could be applied conveniently to soils under three-dimensional stress states.It was shown by comparison between the predicted and test results that the stress-strain properties of overconsolidated clays with stress-induced initial anisotropy could be well described by this model.