Documents disponibles écrits par cet auteur

Base capacity of open-ended steel pipe piles in sand / Feng Yu in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1116–1128. Titre : Base capacity of open-ended steel pipe piles in sand Type de document : texte imprimé Auteurs : Feng Yu, Auteur ; Jun Yang, Auteur Année de publication : 2012 Article en page(s) : pp.1116–1128. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Steel  pipe  piles  Sand  Base  capacity  Soil  plugging  Cone  penetration  test  (CPT) Résumé : This paper presents a new method for estimating the base capacity of open-ended steel pipe piles in sand, a difficult problem involving great uncertainty in pile foundation design. The method, referred to as the Hong Kong University (HKU) method, is based on the cone penetration test (CPT), and takes into consideration the mechanisms of annulus and plug resistance mobilization. In this method the annulus resistance is properly linked to the ratio of the pile length to the diameter—a key factor reflecting the influence of pile embedment—whereas the plug resistance is related to the plug length ratio, which reflects the degree of soil plugging in a practical yet rational way. The cone tip resistance is averaged over a zone in the vicinity of the pile base by taking into account the failure mechanism of the piles in sand, the condition of pile embedment (i.e., full or partial embedment), and the effect of soil compressibility. The predictive performance of the new method is assessed against a number of well-documented field tests including two fully instrumented large-diameter offshore piles, and through comparisons with major CPT-based methods in current engineering practice. The assessment indicates that the HKU method has attractive capabilities and advantages that render it a promising option. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000667 [article] Base capacity of open-ended steel pipe piles in sand [texte imprimé] / Feng Yu, Auteur ; Jun Yang, Auteur . - 2012 . - pp.1116–1128. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1116–1128. Mots-clés : Steel  pipe  piles  Sand  Base  capacity  Soil  plugging  Cone  penetration  test  (CPT) Résumé : This paper presents a new method for estimating the base capacity of open-ended steel pipe piles in sand, a difficult problem involving great uncertainty in pile foundation design. The method, referred to as the Hong Kong University (HKU) method, is based on the cone penetration test (CPT), and takes into consideration the mechanisms of annulus and plug resistance mobilization. In this method the annulus resistance is properly linked to the ratio of the pile length to the diameter—a key factor reflecting the influence of pile embedment—whereas the plug resistance is related to the plug length ratio, which reflects the degree of soil plugging in a practical yet rational way. The cone tip resistance is averaged over a zone in the vicinity of the pile base by taking into account the failure mechanism of the piles in sand, the condition of pile embedment (i.e., full or partial embedment), and the effect of soil compressibility. The predictive performance of the new method is assessed against a number of well-documented field tests including two fully instrumented large-diameter offshore piles, and through comparisons with major CPT-based methods in current engineering practice. The assessment indicates that the HKU method has attractive capabilities and advantages that render it a promising option. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000667

Case history of installing instrumented jacked open-ended piles / Jun-wei Liu in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 7 (Juillet 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 7 (Juillet 2012) . - pp. 810–820 Titre : Case history of installing instrumented jacked open-ended piles Type de document : texte imprimé Auteurs : Jun-wei Liu, Auteur ; Zhong-Miao Zhang, Auteur ; Feng Yu, Auteur Année de publication : 2012 Article en page(s) : pp. 810–820 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Concrete  pipe  piles  Field  tests  Soil  plugging  Pore  water  pressure  Jacking  resistance Résumé : Construction effects on pile-soil systems arise from the process of installing displacement piles. This study conducted a comprehensive field test program complemented with laboratory tests to observe the performance of jacking open-ended concrete pipe piles into silt deposits. The jacked piles were examined in a plugged mode during installation. Direct observation on the soil plugs reveal that their formation generally accords with the stratigraphic nature of the layered soils. Soil-arching behavior during pile penetration causes the soil in the shear zone along the inner pipe wall to mainly come from the uppermost layer of the deposit. Laboratory tests on the soil plug shows evident compaction and the tendency increased strength over time. The buildup of the excess pore pressure and radial total stress in the soil is sensitive to the jacking installation procedure. By taking into account the soil displacement related to the plugging degree, the captured peak excess pore pressure at a given horizon can be modeled by the cavity expansion theory that normally adapts to closed-ended pile. The jacking annulus resistance normalized by the cone tip resistance is independent of the penetration depth and the degree of plugging. A considerable portion of the annulus resistance is locked in the pile after installation, decreases a little during adjacent pile installation, and remains stable over a long period. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000638 [article] Case history of installing instrumented jacked open-ended piles [texte imprimé] / Jun-wei Liu, Auteur ; Zhong-Miao Zhang, Auteur ; Feng Yu, Auteur . - 2012 . - pp. 810–820. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 7 (Juillet 2012) . - pp. 810–820 Mots-clés : Concrete  pipe  piles  Field  tests  Soil  plugging  Pore  water  pressure  Jacking  resistance Résumé : Construction effects on pile-soil systems arise from the process of installing displacement piles. This study conducted a comprehensive field test program complemented with laboratory tests to observe the performance of jacking open-ended concrete pipe piles into silt deposits. The jacked piles were examined in a plugged mode during installation. Direct observation on the soil plugs reveal that their formation generally accords with the stratigraphic nature of the layered soils. Soil-arching behavior during pile penetration causes the soil in the shear zone along the inner pipe wall to mainly come from the uppermost layer of the deposit. Laboratory tests on the soil plug shows evident compaction and the tendency increased strength over time. The buildup of the excess pore pressure and radial total stress in the soil is sensitive to the jacking installation procedure. By taking into account the soil displacement related to the plugging degree, the captured peak excess pore pressure at a given horizon can be modeled by the cavity expansion theory that normally adapts to closed-ended pile. The jacking annulus resistance normalized by the cone tip resistance is independent of the penetration depth and the degree of plugging. A considerable portion of the annulus resistance is locked in the pile after installation, decreases a little during adjacent pile installation, and remains stable over a long period. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000638