A consistent calibration process for the Matsuoka–Nakai friction angle under direct simple shear conditions for clay hypoplasticity

Medicus, Gertraud; Kwa, Katherine; Cerfontaine, Benjamin

doi:10.1016/j.compgeo.2022.104888

Cited by 3 publications

(5 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11b the void ratios at the end of primary consolidation at various vertical effective stresses r 0 1 . Both methods can be used for the calibration of the aforementioned parameters as depicted in other works as well Fuentes et al [9]; Medicus et al [23]. Apparently, the data of isotropic consolidation tests shows a higher degree of scatter than the oedometric tests, and thus, the parameters denoted with NCL (isot.)…”

Section: Comparison With Experimental Datamentioning

confidence: 87%

Clay hypoplasticity coupled with small-strain approaches for complex cyclic loading

Medicus,

Tafili,

Bode

et al. 2023

Acta Geotech.

Self Cite

View full text Add to dashboard Cite

Constitutive models that are able to accurately predict cyclic soil behaviour are crucial for finite element design of offshore foundation or railway embankments. Basic hypoplastic models introduce the history of loading in state variables such as the stress and void ratio and are therefore incapable of describing small-strain stiffness and cyclic loading. In this work, clay hypoplasticity is extended with a modified intergranular strain proposed by Duque et al. [3]. The new model is compared to the one coupled previously with ISA based on unconventional as well as complex cyclic loading paths. Abilities and limitations of the models are addressed: (i) showing that both models predict a reduction in strain accumulation with an increasing number of cycles. (ii) For both models pronounced over- and undershooting effects can occur for certain cyclic loading paths and certain parameters. Despite the consensus in the literature, the results show that a yield surface in the (intergranular) strain space is not sufficient to ban these effects. Furthermore, the models’ predictive capabilities are verified with simulations of monotonic and cyclic tests of Lower Rhine clay.

show abstract

Section: Comparison With Experimental Datamentioning

confidence: 87%

Clay hypoplasticity coupled with small-strain approaches for complex cyclic loading

Medicus,

Tafili,

Bode

et al. 2023

Acta Geotech.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Figure 12B displays the stress ratio

q/p^{\prime}

for Lode angles in the range of

-30^\circ \le \alpha _\sigma \le 30^\circ

. For triaxial extension (

\alpha _\sigma =-30^\circ

q/p^{\prime}

6\sin \varphi _c/(3+\sin \varphi _c)

, for triaxial compression (

\alpha _\sigma =30^\circ

q/p^{\prime}

6\sin \varphi _c/(3-\sin \varphi _c)

, for

\alpha _\sigma =0^\circ

, the stress ratio is 38 :

\begin{equation} \frac{q}{p^{\prime}}=\frac{3}{\sqrt {2}}\cdot \sqrt {\frac{18-2K_{\text{MN,c}}}{9-3K_{\text{MN,c}}}}=\sqrt {\frac{12\sin ^2\varphi _c}{3+\sin ^2\varphi _c}} \end{equation}

At high values of

φ_{c}

…”

Section: Discussionmentioning

confidence: 99%

“…Figure 12B displays the stress ratio 𝑞∕𝑝 ′ for Lode angles in the range of −30 • ≤ 𝛼 𝜎 ≤ 30 • . For triaxial extension (𝛼 𝜎 = −30 • ), 𝑞∕𝑝 ′ is 6 sin 𝜑 𝑐 ∕(3 + sin 𝜑 𝑐 ), for triaxial compression (𝛼 𝜎 = 30 • ), 𝑞∕𝑝 ′ is 6 sin 𝜑 𝑐 ∕(3 − sin 𝜑 𝑐 ), for 𝛼 𝜎 = 0 • , the stress ratio is 38 :…”

Section: Discussionmentioning

confidence: 99%

“…Lagioia and Panteghini 9 investigated an elastoplastic model that employs MN for both the yield as well as the plastic potential surfaces. By using a non-associative flow rule for this model, the stress Lode angle at plane-strain failure can be determined from the angle of dilatancy using Equation (38), as shown in Figure 7:…”

Section: Elastoplastic Matsuoka-nakai Modelmentioning

confidence: 99%

“…We simplified Equation ( 38) from an equation originally proposed in Lagioia and Panteghini (in their work labelled as Equation ( 37)). 9 For critical state, the value 𝜓 = 0 • in Equation (38), leads to a Lode angle 𝛼 𝜎 of zero degrees. For 𝜓 = 0 • , the MN plastic potential surface becomes cylindrical (i.e.…”

Section: Elastoplastic Matsuoka-nakai Modelmentioning

confidence: 99%

See 2 more Smart Citations

On the friction dependency of the stress Lode angle

Medicus,

Pouragha,

Ostermann

et al. 2023

Num Anal Meth Geomechanics

Self Cite

View full text Add to dashboard Cite

The shape of the failure locus of a material is significant for its strength predictions. Even when constitutive models include the same critical stress surface, different critical stress ratios can be predicted for an identical applied isochoric strain path. In this article, we investigate critical stress predictions of different constitutive models, which include the surface according to Matsuoka–Nakai (MN). We perform analytical investigations, true triaxial test simulations with hypoplasticity and barodesy, and discrete element modelling (DEM) simulations to investigate the friction dependency of the stress Lode angle. Our results demonstrate that in hypoplasticity, the direction of the deviatoric stress state at critical state depends solely on the direction of the applied deviatoric strain path. In contrast, in barodesy, the predictions are also dependent on the friction angle of the material. In addition, we compare these results with those obtained with a standard elastoplastic MN model. To validate this friction dependency on the stress Lode angle, we conduct DEM simulations. The DEM results qualitatively support the predictions of barodesy and suggest that a higher friction results in a higher Lode angle at critical stress state.

show abstract

Hypoplastic predictions of changes in undrained shear strength during episodic loading

Medicus,

Kwa

2024

Géotechnique Letters

View full text Add to dashboard Cite

Episodic loading patterns of undrained loading and consolidation are relevant to offshore foundation whole-life applications from variable metocean and operational conditions. In related finite element simulations of foundation-soil interactions, the selected constitutive model then has to capture general trends of the soil response due to episodic loading, including changes in shear strength which affects the foundation's capacity. In this study, element test simulations using clay hypoplasticity were performed to investigate the model's capability to capture general trends in the evolution of void ratio and undrained strength which have been observed in direct simple shear (DSS) experiments on normally consolidated clay. Episodic loading in these DSS tests consisted of periods of undrained shear interspersed with consolidation and was applied to samples of normally consolidated Kaolin clay. The clay hypoplastic constitutive model with the intergranular strain extension can be used to capture the response of normally consolidated clay subjected to episodic loading.

show abstract

A consistent calibration process for the Matsuoka–Nakai friction angle under direct simple shear conditions for clay hypoplasticity

Cited by 3 publications

References 43 publications

Clay hypoplasticity coupled with small-strain approaches for complex cyclic loading

Clay hypoplasticity coupled with small-strain approaches for complex cyclic loading

On the friction dependency of the stress Lode angle

Hypoplastic predictions of changes in undrained shear strength during episodic loading

Contact Info

Product

Resources

About