Clay hypoplasticity model including stiffness anisotropy

Maš́ın, David

doi:10.1680/geot.13.p.065

Cited by 111 publications

(46 citation statements)

References 22 publications

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“…The nonlinearity of soil can be captured by a hypoplastic (HP) constitutive model. Various HP models have been developed in the 1990s (Kolymbas 1991;Gudehus 1996;Von Wolffersdorff 1996;Wu et al 1996) as well as recently (Mašín 2012(Mašín , 2013(Mašín , 2014. The model proposed by Von Wolffersdorff (1996) was adopted to describe the behaviour of Toyoura sand.…”

Section: The Hypoplastic Modelmentioning

confidence: 99%

Ability of three different soil constitutive models to predict a tunnel’s response to basement excavation

Sun

Gan

et al. 2015

Can. Geotech. J.

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Many constitutive models are available nowadays to predict soil-structure interaction problems. It is sometimes not very easier for engineers to select a suitable soil model to carry out their design analyses in terms of complexity versus accuracy. This paper describes the application of three constitutive models to back-analyse a well-instrumented centrifuge model test, in which the effect of basement excavation on an existing tunnel was simulated. These three models include a linear elastic-perfectly plastic model with the Mohr-Coulomb failure criterion (called MC model), a nonlinear elastic Duncan-Chang model (DC) and a hypoplastic model (HP), the last of which can capture path-dependent and strain-dependent soil stiffness even at small strains. By comparing with measured data from the centrifuge model test, it is found that the HP model yielded the best predictions of tunnel heave among the three models. Not only the gradient but also the magnitude of tunnel heave is predicted well by this HP model. This can be explained by the fact that the HP model can capture the path-dependent and strain-dependent soil stiffness even at small strains but not the MC and DC models. However, all three models underestimated the change in tunnel diameter and the maximum tensile bending strain in the transverse direction.

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Section: The Hypoplastic Modelmentioning

confidence: 99%

Ability of three different soil constitutive models to predict a tunnel’s response to basement excavation

Sun

Gan

et al. 2015

Can. Geotech. J.

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“…The UMAT for the following models are available on the webpage soilmodels.info. The hypoplastic model for sand by von Wolffersdorff with and without intergranular strain concept, and The hypoplastic model for undisturbed and remoulded clays by Mašín with and without intergranular strain concept. …”

Section: Availability Of Umatmentioning

confidence: 99%

Genealogy of hypoplasticity and barodesy

Kolymbas

Medicus

2016

Num Anal Meth Geomechanics

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SUMMARYThis article is an attempt at providing an insight into the development of hypoplasticity (including barodesy, which is a recent development of hypoplasticity) as a theory elaborated since 1977, when the first version was published by the first author, until present. The multiplicity of the many versions published since then is hard to overlook. This article presents a review and insight into the evolution of a theory and the struggle to formulate a satisfactory constitutive law. Among the many proposed versions, we focus on those ones that can be seen as changes of paradigm. Copyright © 2016 John Wiley & Sons, Ltd. ON THE DIVERSITY OF CONSTITUTIVE MODELSA constitutive law (or 'constitutive relation' or 'constitutive model') is a theory that describes the mechanical behaviour of a material or class of materials, in our case, soil (and other granular materials). Some scientific communities use the alternative term 'closure equation', as a constitutive equation provides the missing link that is needed next to the balance laws of physics to solve a boundary value problem. Being a theory, a constitutive law is virtually an assumption that can be used as long as it has not been disproved. It is, however, not so straightforward to judge upon falsification of a theory. In the realm of physics, mechanics and, in our case, soil mechanics, theories have always a limited range of validity. Thus, the question whether a particular experimental outcome discredits a theory or not can also be considered as the question whether this outcome falls within the range of validity of the considered theory. Moreover, there is always a deviation between theoretical predictions and experimental outcomes. It is often a subjective judgement whether a deviation is considered as small or large. For these reasons, a constitutive law cannot be simply rated as 'right' or 'wrong', there are many nuances between these attributes. In case a constitutive law provides a prediction judged as non-satisfactory, the question arises whether the shortage can be removed by a modification or it is due to an inherent conceptual failure of the underlying theory. Thus, theories can be either modified or abandoned and replaced by completely new ones.The emergence of a new version not only signifies an improvement but also blames the precedent version for inadequacy. It underlines thus the feeling that a constitutive relation does not mirror a permanent truth. Similar mixed feelings are evoked whenever a new operational system is launched for our computer: the expectation of improved performance is counterbalanced by the displeasure for the necessary rearrangements. In the end, we should realize that perfection is achievable neither for operational systems nor for constitutive relations. The possibility of modifications proves, however, that a given system or theory can still be useful.It should be mentioned that we have refrained from assessing each version by mentioning its advantages and disadvantages, as this would render the paper overly long and is ...

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“…This can partially be attributed to insufficient theoretical knowledge of this model but largely to the need for time consuming calibration (Janda and Šejnoha, 2013;Mašín, 2015). To overcome this burden a research project TA04031604 has been put forward with the aim of providing an automated tool for the determination of basic model parameters as well as of providing a database of these parameters for typical soils based on their standard classification.…”

Section: Formulation Of Hypoplastic Modelmentioning

confidence: 99%

“…All three parameters can be determined from both isotropic compression and oedometric tests. For the latter case, some extra work is needed to properly adjut the parameter N (Janda and Šejnoha, 2013;Mašín, 2015). The envelope of all possible states of soil is represented by the SBS displayed in Figure 1(b), where q stands for the equivalent deviatoric stress.…”

Section: Construction Sitementioning

confidence: 99%

“…Clear message when adopting a hypoplastic model is the need for incorporating the small strain stiffness concept as was the case of HCE model. Even when lacking data derived experimentally for a given soil sample it is still recommended to use the advanced formulation and employ some typical values for intergranular strain parameters (Mašín et al, 2006;Mašín, 2015).…”

Section: Applying Hypoplastic Model For Soft Soils To the Analysis Ofmentioning

confidence: 99%

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Applying hypoplastic model for soft soils to the analysis of anchored sheeting wall

Kadlíček¹

2015

Acta Geodynamica Et Geomaterialia

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This paper is concerned with a practical application of the hypoplastic constitutive model for soft soils. In particular, two specific implementations, so called standard and the one based on smallstrain theory, are considered and the resulting predictions are compared with those provided by the Mohr-Coulomb model. As an example, we considered an anchored underground wall built during the construction of extension of the line A of Prague's subway. The results of all numerical simulations obtained with the help of Geo5 FEM software were also compared with in situ measurements with attention devoted mainly to the evolution of deformation of the underground wall and of pre-stress forces of rope anchors. It is shown that extended formulation of the hypoplastic model accounting for high stiffness of soil at very small strains should be adopted to arrive at reliable and meaningful predictions of the soil response. ARTICLE INFO

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Clay hypoplasticity model including stiffness anisotropy

Cited by 111 publications

References 22 publications

Ability of three different soil constitutive models to predict a tunnel’s response to basement excavation

Ability of three different soil constitutive models to predict a tunnel’s response to basement excavation

Genealogy of hypoplasticity and barodesy

Applying hypoplastic model for soft soils to the analysis of anchored sheeting wall

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