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Effects of principal stress rotation on permanent deformation in rail track foundations / P. J. Gräbe in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 4 (Avril 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 4 (Avril 2009) . - pp. 555–565 Titre : Effects of principal stress rotation on permanent deformation in rail track foundations Type de document : texte imprimé Auteurs : P. J. Gräbe, Auteur ; C. R. Clayton, Auteur Année de publication : 2009 Article en page(s) : pp. 555–565 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Cyclic  loads  Laboratory  tests  Shear  tests  Railroad  tracks  Stress Résumé : A realistic assessment of the whole life cost of rail track foundations requires analysis of the effects of the repeated loadings applied by trains. This paper reports the effects of principal stress rotation (PSR) during cyclic loading on the permanent deformations measured in a series of hollow cylinder tests. The tests were carried out on a number of reconstituted soils selected in order to simulate foundation materials on an existing heavy haul railway line. Typical loadings and track geometry together with dynamic finite-element analyses were used to define representative stress changes to be applied to these soils, which were then tested with and without principal stress rotation during loading. It is shown that principal stress rotation has a significant and deleterious impact on permanent deformation of some materials. Therefore, it is concluded that cyclic triaxial testing, which cannot impose principal stress rotation, will not necessarily give good estimates of the long-term performance of rail track foundations. As PSR cannot be ignored when evaluating permanent displacements of rail track foundations, the use of more appropriate (realistic) testing methods such as the cyclic hollow cylinder or the cyclic simple shear apparatus is required. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A4%2855 [...] [article] Effects of principal stress rotation on permanent deformation in rail track foundations [texte imprimé] / P. J. Gräbe, Auteur ; C. R. Clayton, Auteur . - 2009 . - pp. 555–565. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 4 (Avril 2009) . - pp. 555–565 Mots-clés : Cyclic  loads  Laboratory  tests  Shear  tests  Railroad  tracks  Stress Résumé : A realistic assessment of the whole life cost of rail track foundations requires analysis of the effects of the repeated loadings applied by trains. This paper reports the effects of principal stress rotation (PSR) during cyclic loading on the permanent deformations measured in a series of hollow cylinder tests. The tests were carried out on a number of reconstituted soils selected in order to simulate foundation materials on an existing heavy haul railway line. Typical loadings and track geometry together with dynamic finite-element analyses were used to define representative stress changes to be applied to these soils, which were then tested with and without principal stress rotation during loading. It is shown that principal stress rotation has a significant and deleterious impact on permanent deformation of some materials. Therefore, it is concluded that cyclic triaxial testing, which cannot impose principal stress rotation, will not necessarily give good estimates of the long-term performance of rail track foundations. As PSR cannot be ignored when evaluating permanent displacements of rail track foundations, the use of more appropriate (realistic) testing methods such as the cyclic hollow cylinder or the cyclic simple shear apparatus is required. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A4%2855 [...]