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Identification de lois de comportement enrichies pour les géomatériaux en présence d’une localisation de la déformation

Khadijatou El Moustapha 1, 2
2 GéoMécanique
3SR - Laboratoire sols, solides, structures - risques [Grenoble]
Résumé : The strain localisation modelling of geomaterials requires the use of enhanced models, able to regularise the boundary value problem, by introducing a characteristic length. In this research work, we have chosen to use second gradient models. A question then arises, concerning the identification of second gradient constitutive parameters. This PhD research work aimed to develop an identification method to obtain theses parameters. The study proposed here covers a parametric identification of a constitutive law written in the local second gradient formalism. A part of this identification may be performed through homogenous tests, however the complete identification requires the consideration of high gradient deformation modes, as it is the case where localized deformation is observed. The identification procedure developed uses experimental results from mechanical tests on Vosges sandstone, for which the deformation mode was characterised by kinematic field measurement, including the localized regime. A certain number of observable data can be extracted from these tests, they are then used for the comparison between experimental and numerical data. It is necessary to compute the sensitivity matrix in order to optimise the observables data. In this sense, two sensitivity studies have been carried out, allowing the evaluation of the influence of each constitutive parameter on the selected data. This first analyse concern the homogenous part of the tests. Constitutive parameters involved in this part can be then optimized. The second analyse concerns the localized regime and the sensitivity matrix computation. Once this is achieved, the optimization of the observable data can be conducted. Each observable data can be optimised independently. A set of constitutive parameters is proposed. It allows a good matching between experimental and numerical results at two confining pressures ; 20 and 30 MPa.
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http://hal.univ-grenoble-alpes.fr/tel-02074620
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Soumis le : mercredi 20 mars 2019 - 17:52:31
Dernière modification le : vendredi 3 juillet 2020 - 16:53:12
Document(s) archivé(s) le : vendredi 21 juin 2019 - 22:00:36

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  • HAL Id : tel-02074620, version 1

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CNRS | 3S-R | UGA

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Khadijatou El Moustapha. Identification de lois de comportement enrichies pour les géomatériaux en présence d’une localisation de la déformation. Géotechnique. Université de Grenoble, 2014. Français. ⟨tel-02074620⟩

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