Documents disponibles écrits par cet auteur

Compression and creep of venice lagoon sands / Alex Sanzeni in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 10 (Octobre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 10 (Octobre 2012) . - pp.1266–1276. Titre : Compression and creep of venice lagoon sands Type de document : texte imprimé Auteurs : Alex Sanzeni, Auteur ; Andrew J. Whittle, Auteur ; John T. Germaine, Auteur Année de publication : 2013 Article en page(s) : pp.1266–1276. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Sand  compression  Creep  Soil  behavior  Model  calibration  Venice  Lagoon Résumé : A laboratory test program was conducted to evaluate the one-dimensional (1D) compression and creep properties of intact sand (and silty-sand) samples from a deep borehole at the Malamocco Inlet to the Venice Lagoon. The tests were performed with a constant rate of strain consolidometer and included special procedures for trimming the frozen samples and measuring strains during thawing and backpressure saturation. The specimens had variable fine fractions ranging from 6 to 21% and mica contents ranging from 1 to 10%. The results confirmed that there is a strong correlation between the creep rate coefficient and the compressibility index and between the swelling index and mica content. The compression behavior in all tests is well described by a nonlinear compression model with a unique limiting compression curve and a variable transition parameter that reflects the fines and mica content. Creep tests performed at different confining pressures are also well represented by a simple two-parameter model. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000696 [article] Compression and creep of venice lagoon sands [texte imprimé] / Alex Sanzeni, Auteur ; Andrew J. Whittle, Auteur ; John T. Germaine, Auteur . - 2013 . - pp.1266–1276. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 10 (Octobre 2012) . - pp.1266–1276. Mots-clés : Sand  compression  Creep  Soil  behavior  Model  calibration  Venice  Lagoon Résumé : A laboratory test program was conducted to evaluate the one-dimensional (1D) compression and creep properties of intact sand (and silty-sand) samples from a deep borehole at the Malamocco Inlet to the Venice Lagoon. The tests were performed with a constant rate of strain consolidometer and included special procedures for trimming the frozen samples and measuring strains during thawing and backpressure saturation. The specimens had variable fine fractions ranging from 6 to 21% and mica contents ranging from 1 to 10%. The results confirmed that there is a strong correlation between the creep rate coefficient and the compressibility index and between the swelling index and mica content. The compression behavior in all tests is well described by a nonlinear compression model with a unique limiting compression curve and a variable transition parameter that reflects the fines and mica content. Creep tests performed at different confining pressures are also well represented by a simple two-parameter model. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000696

Experimental study of wellbore instability in clays / Naeem O. Abdulhadi in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 8 (Août 2011) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 8 (Août 2011) . - pp. 766-776 Titre : Experimental study of wellbore instability in clays Type de document : texte imprimé Auteurs : Naeem O. Abdulhadi, Auteur ; John T. Germaine, Auteur ; Andrew J. Whittle, Auteur Année de publication : 2011 Article en page(s) : pp. 766-776 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Borehole  instability  Clays  Laboratory  tests  Model  borehole  tests  Saturated  soils  Shear  strength  Thick-walled  cylinder  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents the results of an extensive program of laboratory model wellbore tests that have been performed to study wellbore instability in saturated clays. The tests were conducted on resedimented Boston blue clay (RBBC) anisotropically consolidated to vertical effective stresses up to 10 MPa by using two custom-built thick-walled cylinder (TWC) devices with outer diameters Do = 7.6 and 15.2 cm. The experimental program investigated the effects of specimen geometry, mode of loading, strain rate, consolidation stress level, and overconsolidation ratio (OCR) on deformations of the model wellbore measured during undrained shearing. Results indicate that for normally consolidated clays most of the change in cavity pressure occurs at volumetric strains less than 5% after which the borehole becomes unstable. Increases in outer diameter and strain rate led to a reduction in the minimum borehole pressure. Stress-strain properties were interpreted by using an analysis procedure originally developed for undrained plane strain expansion of hollow cylinders. The backfigured undrained strength ratios from these analyses for normally consolidated specimens range from su/σvc′ = 0.19–0.22. Overconsolidation greatly improves the stability of the borehole, and interpreted undrained strength ratios from the TWC tests are consistent with well-known power law functions previously developed for elemental shear tests. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i8/p766_s1?isAuthorized=no [article] Experimental study of wellbore instability in clays [texte imprimé] / Naeem O. Abdulhadi, Auteur ; John T. Germaine, Auteur ; Andrew J. Whittle, Auteur . - 2011 . - pp. 766-776. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 8 (Août 2011) . - pp. 766-776 Mots-clés : Borehole  instability  Clays  Laboratory  tests  Model  borehole  tests  Saturated  soils  Shear  strength  Thick-walled  cylinder  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents the results of an extensive program of laboratory model wellbore tests that have been performed to study wellbore instability in saturated clays. The tests were conducted on resedimented Boston blue clay (RBBC) anisotropically consolidated to vertical effective stresses up to 10 MPa by using two custom-built thick-walled cylinder (TWC) devices with outer diameters Do = 7.6 and 15.2 cm. The experimental program investigated the effects of specimen geometry, mode of loading, strain rate, consolidation stress level, and overconsolidation ratio (OCR) on deformations of the model wellbore measured during undrained shearing. Results indicate that for normally consolidated clays most of the change in cavity pressure occurs at volumetric strains less than 5% after which the borehole becomes unstable. Increases in outer diameter and strain rate led to a reduction in the minimum borehole pressure. Stress-strain properties were interpreted by using an analysis procedure originally developed for undrained plane strain expansion of hollow cylinders. The backfigured undrained strength ratios from these analyses for normally consolidated specimens range from su/σvc′ = 0.19–0.22. Overconsolidation greatly improves the stability of the borehole, and interpreted undrained strength ratios from the TWC tests are consistent with well-known power law functions previously developed for elemental shear tests. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i8/p766_s1?isAuthorized=no