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3D FE analyses of buried pipeline with elbows subjected to lateral loading / T. P. Cheong in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 10 (Octobre 2011) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 939-948 Titre : 3D FE analyses of buried pipeline with elbows subjected to lateral loading Type de document : texte imprimé Auteurs : T. P. Cheong, Auteur ; K. Soga, Auteur ; D. J. Robert, Auteur Année de publication : 2012 Article en page(s) : pp. 939-948 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Pipeline  Sand  Finite-element  analysis  Soil-spring  analysis  Lateral  loads Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This study investigates the interaction between soil and pipeline in sand subjected to lateral ground displacements with emphasis on the peak force exerted to a bended elbow-pipe. A series of three-dimensional (3D) finite-element (FE) analyses were performed in both opening and closing modes of the elbow section for different initial pipe bending angles. To model the mechanical behavior of sands, two soil models were adopted: Mohr-Coulomb and Nor-Sand soil model. Investigations also included the effects of pipe embedment depth and soil density. Results show that the opening mode exhibits higher ultimate forces and greater localized deformations than the closing mode. Nondimensional charts that account for pipeline location, bending angle, and soil density are developed. Soil-spring pipeline analyses of an elbow-pipe were performed using modified F-δ soil-spring models based on the 3D FE results and were compared to the findings of conventional spring model analyses using the standard two-dimensional soil-spring model. Results show that the pipe strain does not change in the closing mode case. However, in the opening mode case, the pipe strain computed by the modified analysis is larger than that by the conventional analysis and the difference is more pronounced when the pipe stiffness is stiffer. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i10/p939_s1?isAuthorized=no [article] 3D FE analyses of buried pipeline with elbows subjected to lateral loading [texte imprimé] / T. P. Cheong, Auteur ; K. Soga, Auteur ; D. J. Robert, Auteur . - 2012 . - pp. 939-948. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 939-948 Mots-clés : Pipeline  Sand  Finite-element  analysis  Soil-spring  analysis  Lateral  loads Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This study investigates the interaction between soil and pipeline in sand subjected to lateral ground displacements with emphasis on the peak force exerted to a bended elbow-pipe. A series of three-dimensional (3D) finite-element (FE) analyses were performed in both opening and closing modes of the elbow section for different initial pipe bending angles. To model the mechanical behavior of sands, two soil models were adopted: Mohr-Coulomb and Nor-Sand soil model. Investigations also included the effects of pipe embedment depth and soil density. Results show that the opening mode exhibits higher ultimate forces and greater localized deformations than the closing mode. Nondimensional charts that account for pipeline location, bending angle, and soil density are developed. Soil-spring pipeline analyses of an elbow-pipe were performed using modified F-δ soil-spring models based on the 3D FE results and were compared to the findings of conventional spring model analyses using the standard two-dimensional soil-spring model. Results show that the pipe strain does not change in the closing mode case. However, in the opening mode case, the pipe strain computed by the modified analysis is larger than that by the conventional analysis and the difference is more pronounced when the pipe stiffness is stiffer. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i10/p939_s1?isAuthorized=no

Behaviour of an old masonry tunnel due to tunnelling-induced ground settlement / H. Mohamad in Géotechnique, Vol. 60 N° 12 (Décembre 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 12 (Décembre 2010) . - pp. 927–938 Titre : Behaviour of an old masonry tunnel due to tunnelling-induced ground settlement Type de document : texte imprimé Auteurs : H. Mohamad, Auteur ; P. J. Bennett, Auteur ; K. Soga, Auteur Année de publication : 2011 Article en page(s) : pp. 927–938 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Soil/structure  interaction  Monitoring  Tunnels  Field  instrumentation  Buried  structures  Deformation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A novel technique of distributed strain sensing is introduced using Brillouin optical time-domain reflectometry to examine the performance of an old masonry tunnel during the construction of a new tunnel beneath it in London. Optical fibres attached along the intrados of the tunnel lining at five circumferential sections recorded the relative strains of tunnel deformation between the fixing points as well as detecting localised strain such as cracking in the masonry. The results indicated where cracking might have occurred and were confirmed with visual inspection. Measurements were compared with the data obtained by surveying using total station units and the results show close agreement between the two systems. Flexural behaviour along the longitudinal section of the tunnel was also examined by measuring strain along the springlines and crown. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.074 [article] Behaviour of an old masonry tunnel due to tunnelling-induced ground settlement [texte imprimé] / H. Mohamad, Auteur ; P. J. Bennett, Auteur ; K. Soga, Auteur . - 2011 . - pp. 927–938. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 12 (Décembre 2010) . - pp. 927–938 Mots-clés : Soil/structure  interaction  Monitoring  Tunnels  Field  instrumentation  Buried  structures  Deformation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A novel technique of distributed strain sensing is introduced using Brillouin optical time-domain reflectometry to examine the performance of an old masonry tunnel during the construction of a new tunnel beneath it in London. Optical fibres attached along the intrados of the tunnel lining at five circumferential sections recorded the relative strains of tunnel deformation between the fixing points as well as detecting localised strain such as cracking in the masonry. The results indicated where cracking might have occurred and were confirmed with visual inspection. Measurements were compared with the data obtained by surveying using total station units and the results show close agreement between the two systems. Flexural behaviour along the longitudinal section of the tunnel was also examined by measuring strain along the springlines and crown. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.074

Coupled deformation–flow analysis for methane hydrate extraction / A. Klar in Géotechnique, Vol. 60 N° 10 (Octobre 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 10 (Octobre 2010) . - pp. 765-776 Titre : Coupled deformation–flow analysis for methane hydrate extraction Type de document : texte imprimé Auteurs : A. Klar, Auteur ; K. Soga, Auteur ; M. Y. A. Ng, Auteur Année de publication : 2011 Article en page(s) : pp. 765-776 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Water  flow  Groundwater  Shear  strength  Stress  analysis  Deformation  Permeability  Sands  Constitutive  relations Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Methane hydrate is estimated to be present in substantial amounts below deep sea floors. Particular scientific and engineering interests that encourage studies of mechanical behaviour of methane hydrate soils include submarine geohazards, such as the initiation of marine landslides through hydrate dissociation, wellbore stability and estimation of future gas production from wells. To study these problems, a formulation of a multi-physics model of methane hydrate flow coupled to soil deformation is developed. By assuming deformable porous media (soil matrix) that accommodate non-movable but dissociable hydrate, a two-phase flow formulation of water and methane gas is suggested according to Darcy's law and capillary pressure law. A single-phase elastic–perfectly plastic constitutive model for hydrate soil sediments, based on the concept of effective stress, is developed to account for the effect of hydrate saturation on mechanical strength and stiffness. The formulation is incorporated into the explicit scheme of finite-difference code FLAC by solving three boundary value problems in parallel. The code is used to simulate the behaviour of horizontal unsupported and supported wells in hydrate-bearing sediments under different in situ stress conditions during methane hydrate extraction. Axial force, bending moment and well displacements were compared for supported and unsupported wells. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.079-3799 [article] Coupled deformation–flow analysis for methane hydrate extraction [texte imprimé] / A. Klar, Auteur ; K. Soga, Auteur ; M. Y. A. Ng, Auteur . - 2011 . - pp. 765-776. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 10 (Octobre 2010) . - pp. 765-776 Mots-clés : Water  flow  Groundwater  Shear  strength  Stress  analysis  Deformation  Permeability  Sands  Constitutive  relations Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Methane hydrate is estimated to be present in substantial amounts below deep sea floors. Particular scientific and engineering interests that encourage studies of mechanical behaviour of methane hydrate soils include submarine geohazards, such as the initiation of marine landslides through hydrate dissociation, wellbore stability and estimation of future gas production from wells. To study these problems, a formulation of a multi-physics model of methane hydrate flow coupled to soil deformation is developed. By assuming deformable porous media (soil matrix) that accommodate non-movable but dissociable hydrate, a two-phase flow formulation of water and methane gas is suggested according to Darcy's law and capillary pressure law. A single-phase elastic–perfectly plastic constitutive model for hydrate soil sediments, based on the concept of effective stress, is developed to account for the effect of hydrate saturation on mechanical strength and stiffness. The formulation is incorporated into the explicit scheme of finite-difference code FLAC by solving three boundary value problems in parallel. The code is used to simulate the behaviour of horizontal unsupported and supported wells in hydrate-bearing sediments under different in situ stress conditions during methane hydrate extraction. Axial force, bending moment and well displacements were compared for supported and unsupported wells. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.079-3799

Cross-anisotropic elastic parameters of two natural stiff clays / S. Yimsiri in Géotechnique, Vol. 61 N° 9 (Septembre 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 9 (Septembre 2011) . - pp. 809-814 Titre : Cross-anisotropic elastic parameters of two natural stiff clays Type de document : texte imprimé Auteurs : S. Yimsiri, Auteur ; K. Soga, Auteur Année de publication : 2011 Article en page(s) : pp. 809-814 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Anisotropy  Constitutive  relations  Elasticity  Laboratory  tests  Stiffness Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : An experimental study of the cross-anisotropic elastic parameters was performed on two heavily overconsolidated clays: London Clay and Gault Clay. The study utilised a special triaxial testing apparatus that incorporates local strain measuring system and elastic wave velocity measurement system. Isotropically consolidated drained compression tests and shear wave velocity measurements were undertaken on both vertically and horizontally cut specimens. The experiments were performed under in situ isotropic stresses to study the inherent anisotropic characteristics of the clays in terms of the elastic stiffness. The deformation characteristics during triaxial compression were carefully investigated to obtain various elastic moduli and Poisson ratios. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.072 [article] Cross-anisotropic elastic parameters of two natural stiff clays [texte imprimé] / S. Yimsiri, Auteur ; K. Soga, Auteur . - 2011 . - pp. 809-814. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 9 (Septembre 2011) . - pp. 809-814 Mots-clés : Anisotropy  Constitutive  relations  Elasticity  Laboratory  tests  Stiffness Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : An experimental study of the cross-anisotropic elastic parameters was performed on two heavily overconsolidated clays: London Clay and Gault Clay. The study utilised a special triaxial testing apparatus that incorporates local strain measuring system and elastic wave velocity measurement system. Isotropically consolidated drained compression tests and shear wave velocity measurements were undertaken on both vertically and horizontally cut specimens. The experiments were performed under in situ isotropic stresses to study the inherent anisotropic characteristics of the clays in terms of the elastic stiffness. The deformation characteristics during triaxial compression were carefully investigated to obtain various elastic moduli and Poisson ratios. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.072

Role of linear elasticity in pile group analysis and load test interpretation / Y. F. Leung in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 12 (Décembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 12 (Décembre 2010) . - pp. 1686-1694 Titre : Role of linear elasticity in pile group analysis and load test interpretation Type de document : texte imprimé Auteurs : Y. F. Leung, Auteur ; K. Soga, Auteur ; B. M. Lehane, Auteur Année de publication : 2011 Article en page(s) : pp. 1686-1694 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Pile  groups  Pile  foundations  Soil-pile  interactions Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper compares linear-elastic and nonlinear pile group analysis methods through settlement analyses of hypothetical scenarios and real case studies, and elaborates on the implications for interpretation of pile load test data. Comparisons between linear-elastic and nonlinear methods justify the proposition that pile-to-pile interaction is dominated by linear elasticity, characterized by the small-strain soil stiffness. As the size of a pile group increases, nonlinearity in individual pile behavior becomes overwhelmed by the interaction effects. In such cases, similar estimates will be achieved by both linear and nonlinear methods if the soil modulus is derived from the initial tangent, rather than some secant stiffness, assessed from the load test data. The study clarifies the capabilities and limitations of linear elasticity in pile group analysis and provides guidance on pile test interpretation for analysis of pile group response. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i12/p1686_s1?isAuthorized=no [article] Role of linear elasticity in pile group analysis and load test interpretation [texte imprimé] / Y. F. Leung, Auteur ; K. Soga, Auteur ; B. M. Lehane, Auteur . - 2011 . - pp. 1686-1694. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 12 (Décembre 2010) . - pp. 1686-1694 Mots-clés : Pile  groups  Pile  foundations  Soil-pile  interactions Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper compares linear-elastic and nonlinear pile group analysis methods through settlement analyses of hypothetical scenarios and real case studies, and elaborates on the implications for interpretation of pile load test data. Comparisons between linear-elastic and nonlinear methods justify the proposition that pile-to-pile interaction is dominated by linear elasticity, characterized by the small-strain soil stiffness. As the size of a pile group increases, nonlinearity in individual pile behavior becomes overwhelmed by the interaction effects. In such cases, similar estimates will be achieved by both linear and nonlinear methods if the soil modulus is derived from the initial tangent, rather than some secant stiffness, assessed from the load test data. The study clarifies the capabilities and limitations of linear elasticity in pile group analysis and provides guidance on pile test interpretation for analysis of pile group response. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i12/p1686_s1?isAuthorized=no

A strain space soil model with evolving stiffness anisotropy / K. C. Ellison in Géotechnique, Vol. 62 N° 7 (Juillet 2012) 

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Theoretical study on pile length optimization of pile groups and piled rafts / Y. F. Leung in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 2 (Fevrier 2010) 

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Thermo-mechanical behaviour of energy piles / B. L. Amatya in Géotechnique, Vol. 62 N° 6 (Juin 2012) 

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