Documents disponibles écrits par cet auteur

Dilatancy and shear strength of sand at low confining pressures / T. Chakraborty in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 3 (Mars 2010) . - pp. 527-532 Titre : Dilatancy and shear strength of sand at low confining pressures Type de document : texte imprimé Auteurs : T. Chakraborty, Auteur ; R. Salgado, Auteur Article en page(s) : pp. 527-532 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Sand  Low  confining  stress  Dilatancy  Shear  strength  Friction  angle Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Sand dilates with shearing at a rate that increases with increasing relative density (DR) and decreases with increasing effective confining stress (sigmac[prime]). The peak friction angle of a sand depends on its critical-state friction angle and on dilatancy. In this paper, we develop a simple correlation between peak friction angle, critical-state friction angle, and dilatancy based on triaxial compression and plane-strain compression test data for sand for a range of confining pressures from very low levels to approximately 196 kPa. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...] [article] Dilatancy and shear strength of sand at low confining pressures [texte imprimé] / T. Chakraborty, Auteur ; R. Salgado, Auteur . - pp. 527-532. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 3 (Mars 2010) . - pp. 527-532 Mots-clés : Sand  Low  confining  stress  Dilatancy  Shear  strength  Friction  angle Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Sand dilates with shearing at a rate that increases with increasing relative density (DR) and decreases with increasing effective confining stress (sigmac[prime]). The peak friction angle of a sand depends on its critical-state friction angle and on dilatancy. In this paper, we develop a simple correlation between peak friction angle, critical-state friction angle, and dilatancy based on triaxial compression and plane-strain compression test data for sand for a range of confining pressures from very low levels to approximately 196 kPa. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...]

Effect of relative density and stress level on the bearing capacity of footings on sand / D. Loukidis in Géotechnique, Vol. 61 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 2 (Fevrier 2011) . - pp. 107–119 Titre : Effect of relative density and stress level on the bearing capacity of footings on sand Type de document : texte imprimé Auteurs : D. Loukidis, Auteur ; R. Salgado, Auteur Année de publication : 2011 Article en page(s) : pp. 107–119 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Sands  Bearing  capacity  Anisotropy  Numerical  modelling  Plasticity  Footings/foundations Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The design of shallow foundations relies on bearing capacity values calculated using empirical procedures that are based in part on solutions obtained using the method of characteristics, which assumes a soil that is perfectly plastic following an associated flow rule. In this paper the problem of strip and circular footings resting on the surface of a sand layer is analysed using the finite-element method. Analyses are performed using a two-surface plasticity constitutive model that realistically captures the aspects of the mechanical response of sands that are relevant to the bearing capacity problem. In particular, the model accounts for non-associated flow, strain-softening, and both stress-induced and inherent anisotropy. Based on the results of the analyses, the paper examines the validity of the bearing capacity factors N γ and shape factors s γ used in practice. A relationship for determining appropriate values of friction angle for use in bearing capacity calculations is also proposed. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.150.3771 [article] Effect of relative density and stress level on the bearing capacity of footings on sand [texte imprimé] / D. Loukidis, Auteur ; R. Salgado, Auteur . - 2011 . - pp. 107–119. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 2 (Fevrier 2011) . - pp. 107–119 Mots-clés : Sands  Bearing  capacity  Anisotropy  Numerical  modelling  Plasticity  Footings/foundations Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The design of shallow foundations relies on bearing capacity values calculated using empirical procedures that are based in part on solutions obtained using the method of characteristics, which assumes a soil that is perfectly plastic following an associated flow rule. In this paper the problem of strip and circular footings resting on the surface of a sand layer is analysed using the finite-element method. Analyses are performed using a two-surface plasticity constitutive model that realistically captures the aspects of the mechanical response of sands that are relevant to the bearing capacity problem. In particular, the model accounts for non-associated flow, strain-softening, and both stress-induced and inherent anisotropy. Based on the results of the analyses, the paper examines the validity of the bearing capacity factors N γ and shape factors s γ used in practice. A relationship for determining appropriate values of friction angle for use in bearing capacity calculations is also proposed. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.150.3771

Load and resistance factors for external stability checks of mechanically stabilized earth walls / D. Kim in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 3 (Mars 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 241-251 Titre : Load and resistance factors for external stability checks of mechanically stabilized earth walls Type de document : texte imprimé Auteurs : D. Kim, Auteur ; R. Salgado, Auteur Année de publication : 2012 Article en page(s) : pp. 241-251 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Load  and  resistance  factor  design  External  stability  MSE  wall  Ultimate  limit  state  Reliability  analysis  Target  reliability  index  First-order  reliability  method Résumé : The use of load and resistance factor design (LRFD) to design geotechnical components of transportation infrastructure in the United States is now mandated by the Federal Highway Administration (FHWA). The advantages of LRFD over working stress design (WSD) may lead to its gradual adoption in geotechnical design even in the absence of any mandates. If load and resistance factors are based on reliability analysis, a mechanically stabilized earth (MSE) wall may be designed to a target reliability index (or a target probability of failure). Load and resistance factor design of MSE walls must consider multiple ultimate limit states, associated with both external and internal stabilities. This paper develops factors for use for the two ultimate limit states, sliding and overturning, used in design that are related to the external stability of MSE walls. Equations that closely reproduce the ultimate limit states with as little uncertainty as possible are proposed. The uncertainties of the parameters and the transformations for ultimate limit state equations are assessed using data from an extensive literature review. The first-order reliability method (FORM) is then used to produce resistance factor values for each limit state for different levels of target reliability index. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i3/p241_s1?isAuthorized=no [article] Load and resistance factors for external stability checks of mechanically stabilized earth walls [texte imprimé] / D. Kim, Auteur ; R. Salgado, Auteur . - 2012 . - pp. 241-251. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 241-251 Mots-clés : Load  and  resistance  factor  design  External  stability  MSE  wall  Ultimate  limit  state  Reliability  analysis  Target  reliability  index  First-order  reliability  method Résumé : The use of load and resistance factor design (LRFD) to design geotechnical components of transportation infrastructure in the United States is now mandated by the Federal Highway Administration (FHWA). The advantages of LRFD over working stress design (WSD) may lead to its gradual adoption in geotechnical design even in the absence of any mandates. If load and resistance factors are based on reliability analysis, a mechanically stabilized earth (MSE) wall may be designed to a target reliability index (or a target probability of failure). Load and resistance factor design of MSE walls must consider multiple ultimate limit states, associated with both external and internal stabilities. This paper develops factors for use for the two ultimate limit states, sliding and overturning, used in design that are related to the external stability of MSE walls. Equations that closely reproduce the ultimate limit states with as little uncertainty as possible are proposed. The uncertainties of the parameters and the transformations for ultimate limit state equations are assessed using data from an extensive literature review. The first-order reliability method (FORM) is then used to produce resistance factor values for each limit state for different levels of target reliability index. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i3/p241_s1?isAuthorized=no

Stress–dilatancy relation for Mohr–Coulomb soils following a non-associated flow rule / J. Zhang in Géotechnique, Vol. 60 N° 3 (Mars 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 3 (Mars 2010) . - pp. 223–226 Titre : Stress–dilatancy relation for Mohr–Coulomb soils following a non-associated flow rule Type de document : texte imprimé Auteurs : J. Zhang, Auteur ; R. Salgado, Auteur Année de publication : 2011 Article en page(s) : pp. 223–226 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Constitutive  relations  Failure  Shear  strength  Friction  Deformation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Rowe's stress–dilatancy relation for frictional (cohesionless) materials has been a cornerstone of soil mechanics. The original derivation of this relationship was based on incorrect energy minimisation considerations, but the relationship was proven later by De Josselin de Jong using friction laws, and has been confirmed by a large body of experimental results. In contrast, the validity of Rowe's stress–dilatancy relation for cohesive-frictional materials, which has also been used, although not as extensively, was never verified. This paper shows that Rowe's stress–dilatancy relation for Mohr–Coulomb soils (cohesive-frictional materials) is in fact incorrect. The paper also provides a correct stress–dilatancy relationship for non-associated Mohr–Coulomb soils that have both cohesive and frictional strength components. The derivation of the relationship for cohesive-frictional soils presented in this paper relies on use of the sawtooth model together with the application of the laws of friction. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.t.039 [article] Stress–dilatancy relation for Mohr–Coulomb soils following a non-associated flow rule [texte imprimé] / J. Zhang, Auteur ; R. Salgado, Auteur . - 2011 . - pp. 223–226. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 3 (Mars 2010) . - pp. 223–226 Mots-clés : Constitutive  relations  Failure  Shear  strength  Friction  Deformation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Rowe's stress–dilatancy relation for frictional (cohesionless) materials has been a cornerstone of soil mechanics. The original derivation of this relationship was based on incorrect energy minimisation considerations, but the relationship was proven later by De Josselin de Jong using friction laws, and has been confirmed by a large body of experimental results. In contrast, the validity of Rowe's stress–dilatancy relation for cohesive-frictional materials, which has also been used, although not as extensively, was never verified. This paper shows that Rowe's stress–dilatancy relation for Mohr–Coulomb soils (cohesive-frictional materials) is in fact incorrect. The paper also provides a correct stress–dilatancy relationship for non-associated Mohr–Coulomb soils that have both cohesive and frictional strength components. The derivation of the relationship for cohesive-frictional soils presented in this paper relies on use of the sawtooth model together with the application of the laws of friction. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.t.039