Documents disponibles écrits par cet auteur

Axially loaded piles and pile groups embedded in a cross-anisotropic soil / Y. K. Chow in Géotechnique, Vol. 39 N°2 (Juin 1989) 

Public ISBD [article]  in Géotechnique > Vol. 39 N°2 (Juin 1989) . - pp. 203 –212 Titre : Axially loaded piles and pile groups embedded in a cross-anisotropic soil Type de document : texte imprimé Auteurs : Y. K. Chow, Auteur Année de publication : 2007 Article en page(s) : pp. 203 –212 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Piles  Anisotropy  Finite  elements  Soil-structure  interaction  Settlement  Elasticity Résumé : A numerical procedure is presented to study the behaviour of axially loaded piles and pile groups embedded in a cross-anisotropic soil, with isotropy as a special case. The soil profile may be homogeneous or heterogeneous. A parametric study is performed to investigate the influence of soil with anisotropic properties likely to be relevant to London clay. The results demonstrate the significance of soil anisotropy on the stiffness of single piles. However, its influence on pile-soil-pile interaction, as presented as a stiffness reduction factor, is small, whereas soil inhomogeneity has a greater influence. Some of these observations are demonstrated in a case study of a comprehensive field experiment on a row of three tubular piles jacked in London clay. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.2.203 [article] Axially loaded piles and pile groups embedded in a cross-anisotropic soil [texte imprimé] / Y. K. Chow, Auteur . - 2007 . - pp. 203 –212. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 39 N°2 (Juin 1989) . - pp. 203 –212 Mots-clés : Piles  Anisotropy  Finite  elements  Soil-structure  interaction  Settlement  Elasticity Résumé : A numerical procedure is presented to study the behaviour of axially loaded piles and pile groups embedded in a cross-anisotropic soil, with isotropy as a special case. The soil profile may be homogeneous or heterogeneous. A parametric study is performed to investigate the influence of soil with anisotropic properties likely to be relevant to London clay. The results demonstrate the significance of soil anisotropy on the stiffness of single piles. However, its influence on pile-soil-pile interaction, as presented as a stiffness reduction factor, is small, whereas soil inhomogeneity has a greater influence. Some of these observations are demonstrated in a case study of a comprehensive field experiment on a row of three tubular piles jacked in London clay. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.2.203

Behavior of pile groups subject to excavation-induced soil movement in very soft clay / D. E. L. Ong in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 10 (Octobre 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 10 (Octobre 2009) . - pp. 1462–1474 Titre : Behavior of pile groups subject to excavation-induced soil movement in very soft clay Type de document : texte imprimé Auteurs : D. E. L. Ong, Auteur ; C. F. Leung, Auteur ; Y. K. Chow, Auteur Année de publication : 2009 Article en page(s) : pp. 1462–1474 Note générale : Géotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Pile  groupsBendingCentrifuge  modelsClaysDeflectionExcavationRetaining  wallsSoil  pressure Résumé : A series of centrifuge model tests was conducted to investigate the behavior of pile groups of various sizes and configurations behind a retaining wall in very soft clay. With a 1.2-m excavation in front of the wall, which may simulate the initial stage of an excavation prior to strutting, the test results reveal that the induced bending moment on an individual pile in a free-head pile group is always smaller than that on a corresponding single pile located at the same distance behind the wall. This is attributed to the shadowing and reinforcing effects of other piles within the group. The degree of shadowing experienced by a pile depends on its relative position in the pile group. With a capped-head pile group, the individual piles are forced to interact in unison though subjected to different magnitudes of soil movement. Thus, despite being subjected to a larger soil movement, the induced bending moment on the front piles is moderated by the rear piles through the pile cap. A finite element program developed at the National University of Singapore is employed to back-analyze the centrifuge test data. The program gives a reasonably good prediction of the induced pile bending moments provided an appropriate modification factor is applied for the free-field soil movement and the amount of restraint provided by the pile cap is properly accounted for. The modification factor applied to the free-field soil movement accounts the reinforcing effect of the piles on the soil movement. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000095 [article] Behavior of pile groups subject to excavation-induced soil movement in very soft clay [texte imprimé] / D. E. L. Ong, Auteur ; C. F. Leung, Auteur ; Y. K. Chow, Auteur . - 2009 . - pp. 1462–1474. Géotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 10 (Octobre 2009) . - pp. 1462–1474 Mots-clés : Pile  groupsBendingCentrifuge  modelsClaysDeflectionExcavationRetaining  wallsSoil  pressure Résumé : A series of centrifuge model tests was conducted to investigate the behavior of pile groups of various sizes and configurations behind a retaining wall in very soft clay. With a 1.2-m excavation in front of the wall, which may simulate the initial stage of an excavation prior to strutting, the test results reveal that the induced bending moment on an individual pile in a free-head pile group is always smaller than that on a corresponding single pile located at the same distance behind the wall. This is attributed to the shadowing and reinforcing effects of other piles within the group. The degree of shadowing experienced by a pile depends on its relative position in the pile group. With a capped-head pile group, the individual piles are forced to interact in unison though subjected to different magnitudes of soil movement. Thus, despite being subjected to a larger soil movement, the induced bending moment on the front piles is moderated by the rear piles through the pile cap. A finite element program developed at the National University of Singapore is employed to back-analyze the centrifuge test data. The program gives a reasonably good prediction of the induced pile bending moments provided an appropriate modification factor is applied for the free-field soil movement and the amount of restraint provided by the pile cap is properly accounted for. The modification factor applied to the free-field soil movement accounts the reinforcing effect of the piles on the soil movement. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000095

Centrifuge model study of spudcan penetration in sand overlying clay / K. L. Teh in Géotechnique, Vol. 60 N° 11 (Novembre 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 11 (Novembre 2010) . - pp. 825–842 Titre : Centrifuge model study of spudcan penetration in sand overlying clay Type de document : texte imprimé Auteurs : K. L. Teh, Auteur ; C. F. Leung, Auteur ; Y. K. Chow, Auteur Année de publication : 2011 Article en page(s) : pp. 825–842 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Bearing  capacity  Sands  Footings/foundations  Centrifuge  modelling  Clays  Offshore  engineering Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A series of centrifuge model tests has been conducted to investigate the bearing resistance of spudcan foundations of offshore jack-up rigs in sand overlying normally consolidated clay. The spudcan bearing-resistance profiles measured in most of the tests recorded a peak resistance at a shallow depth within the upper sand layer, followed by an abrupt post-peak reduction in resistance causing the spudcan to plunge into the underlying soft clay. This phenomenon is commonly termed as ‘spudcan punch-through hazard', which potentially leads to severe structural damage of jack-up rigs in the field. The centrifuge test results revealed that the ratio of upper sand layer thickness over spudcan diameter and the ratio of bearing resistance between the upper sand and underlying clay affect the development of spudcan bearing resistance. The limitations of existing design methods, which were derived for the ultimate bearing capacity of pre-embedded shallow foundation to assess the spudcan bearing resistance-depth profile, are also identified. It is proposed that the profile may be assessed by focusing on three key characteristic bearing resistances. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.077 [article] Centrifuge model study of spudcan penetration in sand overlying clay [texte imprimé] / K. L. Teh, Auteur ; C. F. Leung, Auteur ; Y. K. Chow, Auteur . - 2011 . - pp. 825–842. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 11 (Novembre 2010) . - pp. 825–842 Mots-clés : Bearing  capacity  Sands  Footings/foundations  Centrifuge  modelling  Clays  Offshore  engineering Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A series of centrifuge model tests has been conducted to investigate the bearing resistance of spudcan foundations of offshore jack-up rigs in sand overlying normally consolidated clay. The spudcan bearing-resistance profiles measured in most of the tests recorded a peak resistance at a shallow depth within the upper sand layer, followed by an abrupt post-peak reduction in resistance causing the spudcan to plunge into the underlying soft clay. This phenomenon is commonly termed as ‘spudcan punch-through hazard', which potentially leads to severe structural damage of jack-up rigs in the field. The centrifuge test results revealed that the ratio of upper sand layer thickness over spudcan diameter and the ratio of bearing resistance between the upper sand and underlying clay affect the development of spudcan bearing resistance. The limitations of existing design methods, which were derived for the ultimate bearing capacity of pre-embedded shallow foundation to assess the spudcan bearing resistance-depth profile, are also identified. It is proposed that the profile may be assessed by focusing on three key characteristic bearing resistances. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.077

Centrifuge modelling of spudcan–pile interaction in soft clay / Y. Xie in Géotechnique, Vol. 62 N° 9 (Septembre 2012) 

Public ISBD [article]  in Géotechnique > Vol. 62 N° 9 (Septembre 2012) . - pp. 799 –810 Titre : Centrifuge modelling of spudcan–pile interaction in soft clay Type de document : texte imprimé Auteurs : Y. Xie, Auteur ; C. F. Leung, Auteur ; Y. K. Chow, Auteur Année de publication : 2012 Article en page(s) : pp. 799 –810 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Soil/structure  interaction  Clays  Piles  Offshore  engineering  Footings/foundations  Centrifuge  modelling Résumé : The installation and extraction of jack-up spudcans may induce significant stresses in the adjacent piles supporting the permanent jacket platforms at an offshore site. In the present study, centrifuge model tests were conducted to investigate the effects of spudcan movements on the lateral and axial behaviour of adjacent fixed-head piles embedded in soft clay. Parameters such as jack-up operation period, clearance between the spudcan and pile, and the embedment length of the pile are examined. The test results show that the most critical period for platform piles is at the end of spudcan installation, and the lateral pile behaviour is more severely affected than the axial pile behaviour. During spudcan installation, the induced bending moment on a pile located one-quarter spudcan diameter away from the spudcan edge is about 2·4 times that of a pile located one spudcan diameter away. For a deeply buried spudcan with penetration of over three-quarters spudcan diameter, the induced bending moment on longer piles is much smaller than that on shorter piles. The experimental findings provide further insights into the underlying mechanisms governing spudcan–pile interaction in soft clay under various configurations and conditions. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.12.OG.003 [article] Centrifuge modelling of spudcan–pile interaction in soft clay [texte imprimé] / Y. Xie, Auteur ; C. F. Leung, Auteur ; Y. K. Chow, Auteur . - 2012 . - pp. 799 –810. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 62 N° 9 (Septembre 2012) . - pp. 799 –810 Mots-clés : Soil/structure  interaction  Clays  Piles  Offshore  engineering  Footings/foundations  Centrifuge  modelling Résumé : The installation and extraction of jack-up spudcans may induce significant stresses in the adjacent piles supporting the permanent jacket platforms at an offshore site. In the present study, centrifuge model tests were conducted to investigate the effects of spudcan movements on the lateral and axial behaviour of adjacent fixed-head piles embedded in soft clay. Parameters such as jack-up operation period, clearance between the spudcan and pile, and the embedment length of the pile are examined. The test results show that the most critical period for platform piles is at the end of spudcan installation, and the lateral pile behaviour is more severely affected than the axial pile behaviour. During spudcan installation, the induced bending moment on a pile located one-quarter spudcan diameter away from the spudcan edge is about 2·4 times that of a pile located one spudcan diameter away. For a deeply buried spudcan with penetration of over three-quarters spudcan diameter, the induced bending moment on longer piles is much smaller than that on shorter piles. The experimental findings provide further insights into the underlying mechanisms governing spudcan–pile interaction in soft clay under various configurations and conditions. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.12.OG.003