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Cam-clay and hydraulic conductivity diagram relations in consolidated and sheared clay-matrices

  • P. Dudoignon (a1), D. Gélard (a2) and S. Sammartino (a3)


Image analyses, carried out on thin sections made in consolidated and sheared kaolinite test pieces, allow the identification of three ‘microstructural domains’: (1) the initial isotropic matrix; (2) a partly anisotropic matrix resulting from simple particle arrangement; and (3) an anisotropic matrix resulting from rearrangement plus flattening and delamination of particles.

In order to explain the micromechanisms of the clay matrix behaviour, this paper proposes to link the ‘microstructural domains’ represented in the e vs. log p Cam-clay diagram and domains of hydraulic conductivity in the k vs. e diagram.

The hydraulic conductivities are calculated following the Kozeny-Carman relations, which take into account the micro-arrangement of particles via a tortuosity calculation. The generation of 2D images shows that the preservation of the isotropic arrangement of particles is limited by a minimum porosity value. A decrease of the porosity value below this limit can be explained only by a progressive anisotropic rearrangement of the particles.

The microtexture behaviour, induced by the superimposition of the compaction, orientation and particle flattening and delamination stages, causes an anisotropy of the hydraulic conductivity which affects (1) the interstitial water flow direction, (2) the rotation of particles itself, and (3) the damage mechanism of the clay.


L'analyse d'image appliquée à l'étude pétrographique de lames minces, d'éprouvettes de kaolin consolidées et cisaillées, permet d'identifier trois types de microtexture: (1) la microtexture isotrope; (2) la microtexture partiellement anisotrope due à la simple rotation des particules; et (3) la microtexture anisotrope due à la rotation plus l'écrasement des particules.

Pour expliquer les micro-mécanismes de comportement des matrices argileuses sous contraintes, ce travail propose de faire un parallèle entre ces domaines microtexturaux définis dans la représentation de Cam-clay (e en fonction de log p) et des domaines de conductivités hydrauliques (k) représentés dans un diagramme k en fonction de e. Les conductivités hydrauliques sont calculées à partir des équations de Kozeny-Carman qui permettent de prendre en compte l'arrangement des particules via le calcul de tortuosité. La génération d'images 2D montre que l'arrangement des particules est en partie gouverné par les limites inférieures de porosité propres aux différentes microtextures isotrope à anisotrope.

Au cours des phases de consolidation et de cisaillement, l'évolution microstructurale du matériau argileux provoque une anisotropie de k qui agit sur les écoulements d'eau interstitielle, sur la rotation même des particules et sur les mécanismes d'endommagement des matrices argileuses.


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Arch, J. & Maltman, A. (1990) Anisotropic permeability and tortuosity wet sediments. Journal of Geophysical Research, 95, 9035–9045.
Bai, X. & Smart, P. (1997) Change in microstructure of kaolin in consolidation and undrained shear. Géotechnique, 47, 1009–1017.
Bai, X., Smart, P. & Leng, X. (1994) Polarizing microphotometric analysis. Géotechnique, 44, 175–180.
Bennett, R.H., O’Brien, N.R. & Hubert, M.H. (1990) Determinants of clay and shale microfabric signatures: processes and mechanisms. Pp. 5–32 in: Microstructure of the Fine-grained Sediments (Bennett, R.H. et al., editors). Springer, Heidelberg, Germany.
Bennett, R.H., Bryant, W.R. & Hubert, M.H. (1994) Microstructure of the Fine Clay Sediments. From Mud to Shale. Springer-Verlag, New York, 567 pp.
Coster, M. & Chermant, J.L. (1989) Précis d’analyse d’images. Presses du C.N.R.S., France, 560 pp.
David, C. (1993) Geometry of flow paths for fluid transport in rocks. Journal of Geophysical Research, 98, 12267–12278.
David, C. (1994) Fluid flow in rocks: evidence for the existence of preferred percolation paths. In: Cracks Systems in Rocks (Meredith, P., editor). Gordon and Breach, New York.
Djéran-Maigre, I., Tessier, D., Grunberger, D., Velde, B. & Vasseur, G. (1998) Evolution of microstructures and of macroscopic properties of some clays during experimental compaction. Marine and Petroleum Geology, 15, 109–128.
Dudoignon, P., Pantet, A. & Serra, H. (1998) Analyse d’images de géomatèriaux argileux. Revue Française de Génie-Civil, 2, 879–904.
Dudoignon, P., Pantet, A., Carrara, L. & Velde, B. (2001) Macro-micro measurement of particle arrangement in sheared kaolinitic matrices. Géotechnique, 51, 493–499.
Dvorkin, J., Gvirtzman, H. & Nur, A. (1991) Kozeny- Carman relation for a medium with tapered cracks. Geophysical Research Letters, 18, 877–880.
Foster, R.H. & De, P.K. (1971) Optical and electron microscopic investigation of shear induced structures in lightly consolidated (soft) and heavily consolidated (hard) kaolinite. Clays and Clay Minerals, 19, 31–47.
Gillot, J.E. (1969) Study of the fabric of fine-grained sediments with the scanning electron microscope. Journal of Sedimentary Petrology, 39, 90–105.
Griffiths, F.J. & Joschi, R.C. (1990) Clay fabric response to consolidation. Applied Clay Science, 5, 37–66.
Grollier, J., Fernandez, J., Hucher, M. & Riss, J. (1991) Les Propriétés Physiques des Roches, Théories et Modèles. Masson, Paris, 462 pp.
Grumberger, D., Djeran-maigre, I., Velde, B. & Tessier, D. (1994) Mesure de la réorientation des particules de kaolinite lors de la compaction par observation directe. Compte Rendus de l’Academie Scientifique, Paris, 318, 627–633.
Kranck, K. (1990) Interparticle grain size relationships resulting from floculation. Pp. 125–133 in: Microstructure of Fine-Grained Sediments. Springer, Heidelberg, Germany.
Lambe, T.M. & Whitman, R.V. (1969) Soil Mechanics. Wiley, New York, 553 pp.
Little, J.A., Muir-Wood, D., Paul, M.A. & Bouazza, A. (1992) Some laboratory measurements of permeability of Bothkennar clay in relation to soil fabric. Géotechnique, 42, 335–361.
Luo, X., Brigaud, F. & Vasseur, G. (1993) Compaction Coefficient of Argillaceous Sediments: their Implications, Significance and Determination. pp. 321–332. Norwegian Petroleum Society in association with Elsevier, Amsterdam.
McKyes, E. & Yong, R.N. (1971) Results of three techniques for fabric viewing as applied to shear distortion of clay. Clays and Clay Minerals, 19, 289–293.
Meade, R.H. (1964) Removal of water and rearrangement of particles during the compaction of the clayey sediments. US Geological Survey Professional Paper, 450-B, B1–B23.
Mitchell, J.K. (1993) Fundamentals of Soil Behaviour, 2nd edition. John Wiley & Sons, New York, 437 pp.
Morgenstern, N.R. & Tchalenko, J.S. (967) The optical determination of preferred orientation in clays and its applications to the study of microstructure in consolidated kaolin. Proceedings of the Royal Society, A300, 218–250.
Nagaraj, T.S., Pandian, N.S. & Narasimha Raju, P.S.R. (1994) Stress-state permeability relations for overconsolidated clays. Géotechnique, 44, 349–352.
Pantaloni, J. (1998) Ecoulement de fluide. Ecoulement en milieu poreux, Séminaire ‘Les procédés de séparation’. Comité français de l’électricité, France, 32 pp.
Rieke, H. & Chilingarian, G.V. (1974) Compaction of Argillaceous Sediments. Developments in Sedimentology, 16, 424 pp. Elsevier Scientific Publishing Company, Amsterdam.
Sammartino, S., Sardini, P., Moreau, E. & Touchard, G. (1998) Connectivity evolution of 2D random distributions of disks and ellipses: Application to Polyphasic crystal rock distribution. Acta Stereologica, 17, 309–314.
Sardini, P., Sammartino, S., Moreau, E., Meunier, A. & Tevissen, E. (1999) Evolution of fluid pathways of Charroux-Civray Tonalite (part II): numerical study of microcrack networks. Physics and Chemistry of the Earth (A), 24, 621–625.
Skempton, A.W. (1970) The consolidation of clays by gravitational compaction. Quarterly Journal of the Geological Society of London, 125, 99, 373–411.
Terzaghi, K. & Peck, R.B. (1948) Soil Mechanics in Engineering Practices. John Wiley, Chichester, UK, 566 pp.
Tsang, Y.W. (1984) The effect of tortuosity on fluid flow through a single fracture. Water Resource Research, 20, 1209–1215.



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