Effective Stress based Model for Natural Soft Clays incorporating Restructuration

Abstract

Several advanced constitutive models have been developed over the last decades to reproduce the mechanical response of natural soft clays observed during laboratory testing and in the field. Features such as anisotropy, rate-dependence (creep) and the effect of structure (destructuration) are typically implemented in constitutive models using various approaches. This paper describes the development of an effective stress based model for natural soft clays, which incorporates the features earlier mentioned, as well as a new concept for regaining of structure (bondings) over time. The regaining of structure introduces a link between the development of creep strains and the amount of regained structure through the intrinsic reference surface and the apparent reference surface. The constitutive model is based on the assumption of associated flow and utilizes three hardening laws, which introduces eight hardening parameters in total. The model has been implemented in computer code for use in the finite element application PLAXIS as a user defined soil model. The user defined soil model is called SCA-R “Structure, Creep, Anisotropy – Restructuration”. Examples of application are presented and the results are discussed.