Documents disponibles écrits par cet auteur

Analysis of factors influencing soil classification using normalized piezocone tip resistance and pore pressure parameters / James A. Schneider in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1569–1586 Titre : Analysis of factors influencing soil classification using normalized piezocone tip resistance and pore pressure parameters Type de document : texte imprimé Auteurs : James A. Schneider, Auteur ; Mark F. Randolph, Auteur ; Paul W. Mayne, Auteur Année de publication : 2009 Article en page(s) : pp. 1569–1586 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil  classification  Cone  penetration  tests  Silts  Clays  Overconsolidated  soils Résumé : This paper discusses the development of a framework for classifying soil using normalized piezocone test (CPTU) data from the corrected tip resistance (qt) and penetration pore-water pressure at the shoulder (u2) . Parametric studies for normalized cone tip resistance (Q=qcnet/σ′v0) and normalized excess pressures (Δu2/σ′v0) as a function of overconsolidation ratio (OCR=σ′vy/σ′v0) during undrained penetration are combined with piezocone data from clay sites, as well as results from relatively uniform thick deposits of sands, silts, and varietal clays from around the globe. The study focuses on separating the influence of yield stress ratio from that of partial consolidation on normalized CPTU parameters, which both tend to increase Q and decrease the pore pressure parameter (Bq=Δu2/qcnet) . The resulting recommended classification chart is significantly different from existing charts, and implies that assessment of data in Q–Δu2/σ′v0 space is superior to Q–Bq space when evaluating piezocone data for a range of soil types. Still, there are zones of overlap for silty soils and heavily overconsolidated clays, thus requiring that supplementary information to Q and Δu2/σ′v0 be obtained in unfamiliar geologies, including variable rate penetration tests, dissipation tests, CPT friction ratio, or soil sampling. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Analysis of factors influencing soil classification using normalized piezocone tip resistance and pore pressure parameters [texte imprimé] / James A. Schneider, Auteur ; Mark F. Randolph, Auteur ; Paul W. Mayne, Auteur . - 2009 . - pp. 1569–1586. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1569–1586 Mots-clés : Soil  classification  Cone  penetration  tests  Silts  Clays  Overconsolidated  soils Résumé : This paper discusses the development of a framework for classifying soil using normalized piezocone test (CPTU) data from the corrected tip resistance (qt) and penetration pore-water pressure at the shoulder (u2) . Parametric studies for normalized cone tip resistance (Q=qcnet/σ′v0) and normalized excess pressures (Δu2/σ′v0) as a function of overconsolidation ratio (OCR=σ′vy/σ′v0) during undrained penetration are combined with piezocone data from clay sites, as well as results from relatively uniform thick deposits of sands, silts, and varietal clays from around the globe. The study focuses on separating the influence of yield stress ratio from that of partial consolidation on normalized CPTU parameters, which both tend to increase Q and decrease the pore pressure parameter (Bq=Δu2/qcnet) . The resulting recommended classification chart is significantly different from existing charts, and implies that assessment of data in Q–Δu2/σ′v0 space is superior to Q–Bq space when evaluating piezocone data for a range of soil types. Still, there are zones of overlap for silty soils and heavily overconsolidated clays, thus requiring that supplementary information to Q and Δu2/σ′v0 be obtained in unfamiliar geologies, including variable rate penetration tests, dissipation tests, CPT friction ratio, or soil sampling. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

CPT-Based Method for the Installation of Suction Caissons in Sand / Marc Senders in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N°1 (Janvier 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N°1 (Janvier 2009) . - pp. 14–25 Titre : CPT-Based Method for the Installation of Suction Caissons in Sand Type de document : texte imprimé Auteurs : Marc Senders, Auteur ; Mark F. Randolph, Auteur Année de publication : 2009 Article en page(s) : pp. 14–25 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Suction  Caissons  Sand  Cone  penetration  Installation  Pumps  Centrifuge  models Résumé : A CPT-based method is presented for estimating the self-weight penetration and suction required during the installation of suction caissons in medium dense to dense sand. Existing methods, although fundamental in nature, suffer from the difficulty in estimating key input parameters such as an appropriate bearing factor for the tip resistance and frictional coefficients for skirt friction. Instead, the proposed method is based directly on the cone resistance profile, starting with the Det norske Veritas approach for calculating the installation resistance of skirted foundations. The approach is modified to include a simple linear reduction in end bearing on the skirt tips and internal friction with the level of suction, with those components of resistance assumed to reduce to zero once the suction reaches the critical level corresponding to hydraulic failure of the soil plug. The method is coupled with a seepage model so that, for a given pumping rate, the penetration and corresponding resistance can both be expressed as a function of time. Results of calculations with this complete model are shown to compare well with data from centrifuge model tests and with published data from suction caisson installations. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A1%2814 [...] [article] CPT-Based Method for the Installation of Suction Caissons in Sand [texte imprimé] / Marc Senders, Auteur ; Mark F. Randolph, Auteur . - 2009 . - pp. 14–25. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N°1 (Janvier 2009) . - pp. 14–25 Mots-clés : Suction  Caissons  Sand  Cone  penetration  Installation  Pumps  Centrifuge  models Résumé : A CPT-based method is presented for estimating the self-weight penetration and suction required during the installation of suction caissons in medium dense to dense sand. Existing methods, although fundamental in nature, suffer from the difficulty in estimating key input parameters such as an appropriate bearing factor for the tip resistance and frictional coefficients for skirt friction. Instead, the proposed method is based directly on the cone resistance profile, starting with the Det norske Veritas approach for calculating the installation resistance of skirted foundations. The approach is modified to include a simple linear reduction in end bearing on the skirt tips and internal friction with the level of suction, with those components of resistance assumed to reduce to zero once the suction reaches the critical level corresponding to hydraulic failure of the soil plug. The method is coupled with a seepage model so that, for a given pumping rate, the penetration and corresponding resistance can both be expressed as a function of time. Results of calculations with this complete model are shown to compare well with data from centrifuge model tests and with published data from suction caisson installations. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A1%2814 [...]

Investigations on the dynamic behavior of a small-diameter pile driven in soft clay / Antonio M. L. Alves in Canadian geotechnical journal, Vol. 46 N° 12 (Décembre 2009) 

Public ISBD [article]  in Canadian geotechnical journal > Vol. 46 N° 12 (Décembre 2009) . - pp. 1418–1430 Titre : Investigations on the dynamic behavior of a small-diameter pile driven in soft clay Type de document : texte imprimé Auteurs : Antonio M. L. Alves, Auteur ; Francisco R. Lopes, Auteur ; Mark F. Randolph, Auteur Année de publication : 2010 Article en page(s) : pp. 1418–1430 Note générale : Sciences de la Terre Langues : Anglais (eng) Mots-clés : Dynamic  pile  tests  Soft  clay  Soil  models  Set  up  Essais  dynamiques  de  pieux  Argile  molle  Modèles  de  sol  Installation Résumé : This paper presents results and analyses of the dynamic behavior of a small-diameter pile driven in very soft clay, with its tip embedded to a depth of 4.5 m with a clear distance of 1–1.5 m above a stiffer substratum. The research program included static and dynamic load tests performed over a period of 15 days, with blows from three different drop heights. The dynamic signals were analyzed using two different pile–soil interaction models. The performance of the dynamic models in predicting the shaft and base behavior of the model pile, as well as the change in bearing capacity and in some model parameters the dynamic with time, are addressed in particular. Cet article présente les résultats et analyses du comportement dynamique d’un pieu de faible diamètre enfoncé dans de l’argile très molle, avec sa point à une profondeur de 4,5 m et à une distance libre de 1 à 1,5 m au-dessus d’une fondation plus dure. Le programme de recherche comportait des essais de chargement statiques et dynamiques effectués sur une période 15 jours, et consistaient de coups de trois élévations de chute différentes. Les signaux dynamiques ont été analysés à l’aide de deux modèles différents d’interaction pieu-sol. L’article discute de façon particulière de la performance des modèles dynamiques pour prédire le comportement de l’arbre et de la base du pieu modélisé, ainsi que de la dynamique dans le temps de la capacité portante et d’autres paramètres du modèle. DEWEY : 550 ISSN : 0008-3674 En ligne : http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=f [...] [article] Investigations on the dynamic behavior of a small-diameter pile driven in soft clay [texte imprimé] / Antonio M. L. Alves, Auteur ; Francisco R. Lopes, Auteur ; Mark F. Randolph, Auteur . - 2010 . - pp. 1418–1430. Sciences de la Terre Langues : Anglais (eng) in Canadian geotechnical journal > Vol. 46 N° 12 (Décembre 2009) . - pp. 1418–1430 Mots-clés : Dynamic  pile  tests  Soft  clay  Soil  models  Set  up  Essais  dynamiques  de  pieux  Argile  molle  Modèles  de  sol  Installation Résumé : This paper presents results and analyses of the dynamic behavior of a small-diameter pile driven in very soft clay, with its tip embedded to a depth of 4.5 m with a clear distance of 1–1.5 m above a stiffer substratum. The research program included static and dynamic load tests performed over a period of 15 days, with blows from three different drop heights. The dynamic signals were analyzed using two different pile–soil interaction models. The performance of the dynamic models in predicting the shaft and base behavior of the model pile, as well as the change in bearing capacity and in some model parameters the dynamic with time, are addressed in particular. Cet article présente les résultats et analyses du comportement dynamique d’un pieu de faible diamètre enfoncé dans de l’argile très molle, avec sa point à une profondeur de 4,5 m et à une distance libre de 1 à 1,5 m au-dessus d’une fondation plus dure. Le programme de recherche comportait des essais de chargement statiques et dynamiques effectués sur une période 15 jours, et consistaient de coups de trois élévations de chute différentes. Les signaux dynamiques ont été analysés à l’aide de deux modèles différents d’interaction pieu-sol. L’article discute de façon particulière de la performance des modèles dynamiques pour prédire le comportement de l’arbre et de la base du pieu modélisé, ainsi que de la dynamique dans le temps de la capacité portante et d’autres paramètres du modèle. DEWEY : 550 ISSN : 0008-3674 En ligne : http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=f [...]

Keying of rectangular plate anchors in normally consolidated clays / Dong Wang in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 12 (Décembre 2011) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 12 (Décembre 2011) . - pp. 1244-1253 Titre : Keying of rectangular plate anchors in normally consolidated clays Type de document : texte imprimé Auteurs : Dong Wang, Auteur ; Yuxia Hu, Auteur ; Mark F. Randolph, Auteur Année de publication : 2012 Article en page(s) : pp. 1244-1253 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Finite-element  method  Plate  anchor  Uplift  capacity  Normally  consolidated  clay  Keying  Large  deformation  analysis Résumé : The loss in anchor embedment during keying, as it rotates to become normal to the cable load, reduces the uplift capacity of anchors in normally consolidated clay. The keying behavior of plate anchors has been studied previously by using centrifuge and field model tests. In this paper, a large deformation finite-element approach incorporating frequent mesh regeneration and allowing for evolution of the anchor-chain profile, was developed to simulate the keying process of rectangular and strip plate anchors. A parametric study was undertaken to quantify the loss in anchor embedment during keying in terms of the anchor geometry, soil properties, loading eccentricity, and inclination. The embedment loss decreased dramatically with increasing loading eccentricity and decreasing chain angle at the mudline to the horizontal. The loss in anchor embedment during keying increased as the local soil strength increased relative to the weight of the anchor, up to a limit determined by the eccentricity of loading. In contrast, the effect of the soil strength gradient was minimal. Findings of this study yield a recommendation that the most important factor in anchor keying, loading eccentricity, should not be less than half the anchor width for an effective design. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i12/p1244_s1?isAuthorized=no [article] Keying of rectangular plate anchors in normally consolidated clays [texte imprimé] / Dong Wang, Auteur ; Yuxia Hu, Auteur ; Mark F. Randolph, Auteur . - 2012 . - pp. 1244-1253. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 12 (Décembre 2011) . - pp. 1244-1253 Mots-clés : Finite-element  method  Plate  anchor  Uplift  capacity  Normally  consolidated  clay  Keying  Large  deformation  analysis Résumé : The loss in anchor embedment during keying, as it rotates to become normal to the cable load, reduces the uplift capacity of anchors in normally consolidated clay. The keying behavior of plate anchors has been studied previously by using centrifuge and field model tests. In this paper, a large deformation finite-element approach incorporating frequent mesh regeneration and allowing for evolution of the anchor-chain profile, was developed to simulate the keying process of rectangular and strip plate anchors. A parametric study was undertaken to quantify the loss in anchor embedment during keying in terms of the anchor geometry, soil properties, loading eccentricity, and inclination. The embedment loss decreased dramatically with increasing loading eccentricity and decreasing chain angle at the mudline to the horizontal. The loss in anchor embedment during keying increased as the local soil strength increased relative to the weight of the anchor, up to a limit determined by the eccentricity of loading. In contrast, the effect of the soil strength gradient was minimal. Findings of this study yield a recommendation that the most important factor in anchor keying, loading eccentricity, should not be less than half the anchor width for an effective design. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i12/p1244_s1?isAuthorized=no

New mechanism-based design approach for spudcan foundations on single layer clay / Muhammad Shazzad Hossain in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 9 (Septembre 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 9 (Septembre 2009) . - pp. 1264–1274 Titre : New mechanism-based design approach for spudcan foundations on single layer clay Type de document : texte imprimé Auteurs : Muhammad Shazzad Hossain, Auteur ; Mark F. Randolph, Auteur Année de publication : 2009 Article en page(s) : pp. 1264–1274 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Load  bearing  capacityCentrifuge  modelsClaysFinite  element  methodHeterogeneityFoundation  design Résumé : Spudcan foundations for offshore mobile drilling rigs are large saucer-shaped foundations that can penetrate several tens of meters into soft sediments. The penetration depth is typically predicted by considering a wished-in-place foundation at different depths and following traditional bearing capacity approaches to assess the depth at which the estimated capacity matches the applied loading. However, the geometry of the spudcan and its progressive mode of penetration lead to soil failure mechanisms that differ markedly from those relevant to onshore practice. This paper presents a new rational design approach for assessing spudcan penetration in single layer clays based on a study combining centrifuge model testing and large deformation finite-element (FE) analysis. The design approach takes account of the evolving failure mechanisms in the soil, which start with cavity formation and surface heave at shallow penetration, gradually transforming to backflow of soil over the spudcan. A detailed FE parametric study has explored the relevant range of normalized strength, strength nonhomogeneity, and spudcan base roughness, with results validated against centrifuge model test data. The penetration response curves are presented in terms of profiles of bearing capacity factors, forming nondimensional design charts along with simplified expressions for convenient use in practice. Comparisons with approaches suggested in the SNAME design code suggest an urgent need to update current practice. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000054 [article] New mechanism-based design approach for spudcan foundations on single layer clay [texte imprimé] / Muhammad Shazzad Hossain, Auteur ; Mark F. Randolph, Auteur . - 2009 . - pp. 1264–1274. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 9 (Septembre 2009) . - pp. 1264–1274 Mots-clés : Load  bearing  capacityCentrifuge  modelsClaysFinite  element  methodHeterogeneityFoundation  design Résumé : Spudcan foundations for offshore mobile drilling rigs are large saucer-shaped foundations that can penetrate several tens of meters into soft sediments. The penetration depth is typically predicted by considering a wished-in-place foundation at different depths and following traditional bearing capacity approaches to assess the depth at which the estimated capacity matches the applied loading. However, the geometry of the spudcan and its progressive mode of penetration lead to soil failure mechanisms that differ markedly from those relevant to onshore practice. This paper presents a new rational design approach for assessing spudcan penetration in single layer clays based on a study combining centrifuge model testing and large deformation finite-element (FE) analysis. The design approach takes account of the evolving failure mechanisms in the soil, which start with cavity formation and surface heave at shallow penetration, gradually transforming to backflow of soil over the spudcan. A detailed FE parametric study has explored the relevant range of normalized strength, strength nonhomogeneity, and spudcan base roughness, with results validated against centrifuge model test data. The penetration response curves are presented in terms of profiles of bearing capacity factors, forming nondimensional design charts along with simplified expressions for convenient use in practice. Comparisons with approaches suggested in the SNAME design code suggest an urgent need to update current practice. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000054

Numerical simulation of vertical pullout of plate anchors in clay / Zhenhe Song in Journal of geotechnical and geoenvironmental engineering, Vol. 134 N° 6 (Juin 2008) 

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Numerical study of the effect of foundation size for a wide range of sands / Nobutaka Yamamoto in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N°1 (Janvier 2009) 

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Parametric solutions for slide impact on pipelines / Mark F. Randolph in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

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Penetrometer-based assessment of spudcan penetration resistance / Junhwan Lee in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 6 (Juin 2011) 

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Strength measurement for near-seabed surface soft soil using manually operated miniature full-flow penetrometer / Han Eng Low in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 11 (Novembre 2010) 

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Three-dimensional large deformation finite-element analysis of plate anchors in uniform clay / Dong Wang in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 2 (Fevrier 2010) 

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