Experimental analysis of kaolinite particle orientation during triaxial path |
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| Authors: | Mahdia Hattab Jean‐Marie Fleureau |
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| Institution: | 1. Laboratoire de Physique et Mécanique des Matériaux, FRE CNRS 3236, Université Paul Verlaine, Ile du Saulcy – 57045 Metz Cedex1, France;2. Laboratoire de Mécanique des Sols, Structures et Matériaux, UMR CNRS 8579, Ecole Centrale Paris, Grande voie des vignes, 92295 Chatenay Malabry Cedex, France |
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| Abstract: | The goal of this study was to analyze the relation between the behaviour of a clayey material at the macroscopic scale and its microfabric evolution. This may lead to a better understanding of macroscopic strain mechanisms especially the contractancy and dilatancy phenomena. The approach proposed in this paper is based on the study of clay particles orientation by SEM picture analysis after different phases of triaxial loading. In the initial state of the samples (one‐dimensional compression), the SEM observations highlight a microstructural anisotropy with a preferential orientation of the particles normal to the loading direction. During isotropic loading, densification of the clayey matrix occurs related to a random orientation of particles indicated by the term ‘depolarization’. In the earlier stages of constant σ3 drained triaxial path on slightly overconsolidated specimens, the microstructural depolarization seems to persist inside a macroscopic domain, in which only the volumetric strains due to the isotropic part of the stress tensor evolve. Then, a rotation mechanism of the particles towards preferred directions seems to be activated. The phenomenon appears directly linked to the evolution of the deviatoric part of the stress tensor. Copyright © 2010 John Wiley & Sons, Ltd. |
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| Keywords: | consolidation anisotropy microfabric microscopy clay behaviour triaxial tests |
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