Documents disponibles écrits par cet auteur

Identification and description of soils containing very coarse fractions / Fred H. Kulhawy in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 5 (Mai 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 5 (Mai 2009) . - pp. 635–646 Titre : Identification and description of soils containing very coarse fractions Type de document : texte imprimé Auteurs : Fred H. Kulhawy, Auteur ; Jie-Ru Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 635–646 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil  classification  Grain  size  Coarse-grained  soils  Soil  properties Résumé : Current practices are reviewed for the identification, description, and classification of soils containing significant very coarse fractions. The review shows that there are serious shortcomings when these fractions are present. To upgrade current practices, improvements are needed in two areas: (1) the grain-size scale and nomenclature; and (2) the basic system for soil identification. First, an improved grain-size scale is proposed that clarifies the very coarse fractions and other nomenclature. Second, it is shown that current U.S. classification systems can not address the very coarse soils adequately, and they can not be adapted easily to do so. However, a relatively straightforward expansion can be made to the Burmister identification system to incorporate these soils. This Expanded Burmister Soil Identification System is flexible enough to describe and identify soils, ranging from very coarse to very fine, in a complete and consistent manner. Adoption of these two recommendations can improve practice and reduce current ambiguities in dealing with soils containing very coarse fractions. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A5%2863 [...] [article] Identification and description of soils containing very coarse fractions [texte imprimé] / Fred H. Kulhawy, Auteur ; Jie-Ru Chen, Auteur . - 2009 . - pp. 635–646. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 5 (Mai 2009) . - pp. 635–646 Mots-clés : Soil  classification  Grain  size  Coarse-grained  soils  Soil  properties Résumé : Current practices are reviewed for the identification, description, and classification of soils containing significant very coarse fractions. The review shows that there are serious shortcomings when these fractions are present. To upgrade current practices, improvements are needed in two areas: (1) the grain-size scale and nomenclature; and (2) the basic system for soil identification. First, an improved grain-size scale is proposed that clarifies the very coarse fractions and other nomenclature. Second, it is shown that current U.S. classification systems can not address the very coarse soils adequately, and they can not be adapted easily to do so. However, a relatively straightforward expansion can be made to the Burmister identification system to incorporate these soils. This Expanded Burmister Soil Identification System is flexible enough to describe and identify soils, ranging from very coarse to very fine, in a complete and consistent manner. Adoption of these two recommendations can improve practice and reduce current ambiguities in dealing with soils containing very coarse fractions. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A5%2863 [...]

Updating uncertainties in friction angles of clean sands / Jianye Ching in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 2 (Fevrier 2012) . - pp. 217-229 Titre : Updating uncertainties in friction angles of clean sands Type de document : texte imprimé Auteurs : Jianye Ching, Auteur ; Jie-Ru Chen, Auteur ; Jian-Yi Yeh, Auteur Année de publication : 2012 Article en page(s) : pp. 217-229 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Clean  sands  Uncertainty  Friction  angle  Correlation  Bayesian  analysis Résumé : It is essential to characterize the uncertainties of soil shear strengths, including friction angles of sands, for geotechnical reliability-based design. In particular, it is of practical interest to update the uncertainties in friction angles on the basis of all available information by correlation, given the considerable cost of a typical site investigation. Although it is relatively simple to update uncertainties by correlation when the information is one dimensional (1D) or univariate, it is quite challenging to update uncertainties by using multivariate information through multiple correlations. This study proposes a systematic way of constructing multivariate correlations on friction angles of reconstituted clean sands. A set of simplified equations are obtained through Bayesian analysis for the purpose of updating uncertainties. The inputs to the equations are the results of field and laboratory tests, and the outputs are the updated mean values and standard deviations of the friction angles. Test databases are used to demonstrate the consistency of the proposed simplified equations. Results show that uncertainties in friction angles can be effectively reduced by incorporating multivariate information. Given that reliability-based design can justify more economical design with updated uncertainties, the proposed equations essentially link the value of more and/or better tests directly to final design savings. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i2/p217_s1?isAuthorized=no [article] Updating uncertainties in friction angles of clean sands [texte imprimé] / Jianye Ching, Auteur ; Jie-Ru Chen, Auteur ; Jian-Yi Yeh, Auteur . - 2012 . - pp. 217-229. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 2 (Fevrier 2012) . - pp. 217-229 Mots-clés : Clean  sands  Uncertainty  Friction  angle  Correlation  Bayesian  analysis Résumé : It is essential to characterize the uncertainties of soil shear strengths, including friction angles of sands, for geotechnical reliability-based design. In particular, it is of practical interest to update the uncertainties in friction angles on the basis of all available information by correlation, given the considerable cost of a typical site investigation. Although it is relatively simple to update uncertainties by correlation when the information is one dimensional (1D) or univariate, it is quite challenging to update uncertainties by using multivariate information through multiple correlations. This study proposes a systematic way of constructing multivariate correlations on friction angles of reconstituted clean sands. A set of simplified equations are obtained through Bayesian analysis for the purpose of updating uncertainties. The inputs to the equations are the results of field and laboratory tests, and the outputs are the updated mean values and standard deviations of the friction angles. Test databases are used to demonstrate the consistency of the proposed simplified equations. Results show that uncertainties in friction angles can be effectively reduced by incorporating multivariate information. Given that reliability-based design can justify more economical design with updated uncertainties, the proposed equations essentially link the value of more and/or better tests directly to final design savings. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i2/p217_s1?isAuthorized=no