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Mechanical behaviour of unsaturated kaolin (with isotropic and anisotropic stress history). Part 1, Wetting and compression behaviour / V. Sivakumar in Géotechnique, Vol. 60 N° 8 (Août 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 8 (Août 2010) . - pp. 581–594 Titre : Mechanical behaviour of unsaturated kaolin (with isotropic and anisotropic stress history). Part 1, Wetting and compression behaviour Type de document : texte imprimé Auteurs : V. Sivakumar, Auteur ; R. Sivakumar, Auteur ; E. J. Murray, Auteur Année de publication : 2011 Article en page(s) : pp. 581–594 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Clays  Laboratory  tests  Stress  path  Compaction  Anisotropy  Earth  fill Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Over the last 40 years considerable progress has been made in understanding the complex behaviour of unsaturated soils. Research using constitutive modelling has extended the critical state framework and the concept of yielding in saturated soils to encompass unsaturated soils experiencing suction. However, validation testing of the framework for unsaturated soils has shown disagreement with the basic propositions. The main reason for this disparity is the anisotropic properties of the soil specimens tested as a result of preparation using one-dimensional compaction. The paper describes the detailed testing carried out to justify this statement. As part of the work presented, samples of unsaturated kaolin were prepared using isotropic compression. The suctions in these samples were reduced to predefined values by wetting under low isotropic loading. The pore size distributions, the pressure–volume relationships and yielding under subsequent isotropic loading are compared with tests on samples prepared by statically compressing kaolin into a one-dimensional compaction mould. The anisotropically compressed samples had initial water contents and specific volumes similar to those of the isotropically prepared samples and were also tested under reducing suctions; they exhibited distinctly different behaviour when tested under similar conditions. The results obtained from the isotropically prepared and tested samples have shown, probably for the first time, the existence of a unique normal compression surface that is not dependent on the initial conditions of the samples. The shape of the loading–collapse (LC) yield locus is shown to be different from the generally accepted form. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.007 [article] Mechanical behaviour of unsaturated kaolin (with isotropic and anisotropic stress history). Part 1, Wetting and compression behaviour [texte imprimé] / V. Sivakumar, Auteur ; R. Sivakumar, Auteur ; E. J. Murray, Auteur . - 2011 . - pp. 581–594. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 8 (Août 2010) . - pp. 581–594 Mots-clés : Clays  Laboratory  tests  Stress  path  Compaction  Anisotropy  Earth  fill Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Over the last 40 years considerable progress has been made in understanding the complex behaviour of unsaturated soils. Research using constitutive modelling has extended the critical state framework and the concept of yielding in saturated soils to encompass unsaturated soils experiencing suction. However, validation testing of the framework for unsaturated soils has shown disagreement with the basic propositions. The main reason for this disparity is the anisotropic properties of the soil specimens tested as a result of preparation using one-dimensional compaction. The paper describes the detailed testing carried out to justify this statement. As part of the work presented, samples of unsaturated kaolin were prepared using isotropic compression. The suctions in these samples were reduced to predefined values by wetting under low isotropic loading. The pore size distributions, the pressure–volume relationships and yielding under subsequent isotropic loading are compared with tests on samples prepared by statically compressing kaolin into a one-dimensional compaction mould. The anisotropically compressed samples had initial water contents and specific volumes similar to those of the isotropically prepared samples and were also tested under reducing suctions; they exhibited distinctly different behaviour when tested under similar conditions. The results obtained from the isotropically prepared and tested samples have shown, probably for the first time, the existence of a unique normal compression surface that is not dependent on the initial conditions of the samples. The shape of the loading–collapse (LC) yield locus is shown to be different from the generally accepted form. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.007

Resistance of passive inclined anchors in cohesionless medium / E. J. Murray in Géotechnique, Vol. 39 N°3 (Septembre 1989) 

Public ISBD [article]  in Géotechnique > Vol. 39 N°3 (Septembre 1989) . - pp. 417-431 Titre : Resistance of passive inclined anchors in cohesionless medium Type de document : texte imprimé Auteurs : E. J. Murray, Auteur ; J. D. Geddes, Auteur Année de publication : 2007 Article en page(s) : pp. 417-431 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Anchors  Failure  Model  tests  Plasticity  Sands  Soil-structure  interaction Résumé : The passive resistance of inclined anchor plates in sand is examined. Laboratory experimental results are presented for the ultimate passive resistance, and the corresponding displacements, of rectangular anchor plates pulled at angles of inclination between the vertical and the horizontal through very dense sand. The results of ultimate passive resistance are compared with theoretical solutions based on the upper and lower bound limit theorems of soil plasticity. A general lower bound solution for a strip anchor pulled at various angles of loading cannot be readily formulated, and only a poor lower bound solution for the case of horizontal loading is determined. However, it is shown that provided interface friction is taken into account, upper bound solutions for a strip anchor compare favourably with the experimental evidence. Good agreement is shown between the upper bound solutions and the equivalent free surface stress characteristic solution, and experimental data, of Neely et al. (1973) for the horizontal translation of anchor plates in medium dense sand. Comparison is also made between the experimental results of this Paper and the finite element approach of Rowe & Davis (1982) for anchors pulled horizontally through an assumed elastic-plastic soil. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/issue/geot/39/3 [article] Resistance of passive inclined anchors in cohesionless medium [texte imprimé] / E. J. Murray, Auteur ; J. D. Geddes, Auteur . - 2007 . - pp. 417-431. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 39 N°3 (Septembre 1989) . - pp. 417-431 Mots-clés : Anchors  Failure  Model  tests  Plasticity  Sands  Soil-structure  interaction Résumé : The passive resistance of inclined anchor plates in sand is examined. Laboratory experimental results are presented for the ultimate passive resistance, and the corresponding displacements, of rectangular anchor plates pulled at angles of inclination between the vertical and the horizontal through very dense sand. The results of ultimate passive resistance are compared with theoretical solutions based on the upper and lower bound limit theorems of soil plasticity. A general lower bound solution for a strip anchor pulled at various angles of loading cannot be readily formulated, and only a poor lower bound solution for the case of horizontal loading is determined. However, it is shown that provided interface friction is taken into account, upper bound solutions for a strip anchor compare favourably with the experimental evidence. Good agreement is shown between the upper bound solutions and the equivalent free surface stress characteristic solution, and experimental data, of Neely et al. (1973) for the horizontal translation of anchor plates in medium dense sand. Comparison is also made between the experimental results of this Paper and the finite element approach of Rowe & Davis (1982) for anchors pulled horizontally through an assumed elastic-plastic soil. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/issue/geot/39/3