Improvement of a hypoplastic model to predict clay behaviour under undrained conditions

Abstract

A shortcoming of the hypoplastic model for clays proposed by the first author is an incorrect prediction of the initial portion of the undrained stress path, particularly for tests on normally consolidated soils at isotropic stress states. A conceptually simple modification of this model, which overcomes this drawback, is proposed in the contribution. The modified model is applicable to both normally consolidated and overconsolidated soils and predicts the same swept-out-memory states (i.e., normal compression lines) as the original model. At anisotropic stress states and at higher overconsolidation ratios the modified model yields predictions similar to the original model.

Asymptotic behaviour of granular materials

“…Figure 18b, however, demonstrates that the ψ˙ = 90 • path does not follow the ASBSs in the course of loading. This is consistent with predictions of hypoplasticity [39,41,42], but not with predictions of elasto-plastic models based on critical state soil mechanics [52]. The elasto-plastic models imply that in normally consolidated conditions the isochoric stress path follows the state boundary surface up to the asymptotic state.…”

Numerical investigation of the stabilisation behaviour of shallow foundations under alternate loading

“…The hypoplastic model was originally developed for cohesionless materials. Recently, the model was extended to include clayey soils [11,13,17,19,27]. Numerical investigation of boundary value problems using hypoplastic constitutive models was reported by Tejchman et al [26], Henke and Grabe [9] and Salciarini and Tamagnini [22]).…”

Numerical investigation of soil plugging inside open-ended piles with respect to the installation method

“…The hypoplastic model was originally developed for cohesionless soil. Recently, the model has been extended to cohesive soils [7,25,15] and to high order continua [21].…”