Stiffness of Clays and Silts: Normalizing Shear Modulus and Shear Strain
Identifieur interne : 000185 ( Main/Exploration ); précédent : 000184; suivant : 000186Stiffness of Clays and Silts: Normalizing Shear Modulus and Shear Strain
Auteurs : P. J. Vardanega [Royaume-Uni] ; M. D. Bolton [Royaume-Uni]Source :
- Journal of geotechnical and geoenvironmental engineering [ 1090-0241 ] ; 2013.
Descripteurs français
- Pascal (Inist)
- Wicri :
- topic : Base de données.
English descriptors
- KwdEn :
Abstract
An analysis is presented of a database of 67 tests on 21 clays and silts of undrained shear stress-strain data of fine-grained soils. Normalizations of secant G in terms of initial mean effective stress p' (i.e., G/p' versus log γ) or undrained shear strength cu (i.e., G/cu versus log y) are shown to be much less successful in reducing the scatter between different clays than the approach that uses the maximum shear modulus, Gmax, a technique still not universally adopted by geotechnical researchers and constitutive modelers. Analysis of semiempirical expressions for Gmax is presented and a simple expression that uses only a void-ratio function and a confining-stress function is proposed. This is shown to be superior to a Hardin-style equation, and the void ratio function is demonstrated as an alternative to an overconsolidation ratio (OCR) function. To derive correlations that offer reliable estimates of secant stiffness at any required magnitude of working strain, secant shear modulus G is normalized with respect to its small-strain value Gmax, and shear strain γ is normalized with respect to a reference strain γref at which this stiffness has halved. The data are corrected to two standard strain rates to reduce the discrepancy between data obtained from static and cyclic testing. The reference strain γref is approximated as a function of the plasticity index. A unique normalized shear modulus reduction curve in the shape of a modified hyperbola is fitted to all the available data up to shear strains of the order of 1%. As a result, good estimates can be made of the modulus reduction G/Gmax ± 30% across all strain levels in approximately 90% of the cases studied. New design charts are proposed to update the commonly used design curves.
Affiliations:
Links toward previous steps (curation, corpus...)
- to stream PascalFrancis, to step Corpus: 000029
- to stream PascalFrancis, to step Curation: 000735
- to stream PascalFrancis, to step Checkpoint: 000028
- to stream Main, to step Merge: 000188
- to stream Main, to step Curation: 000185
Le document en format XML
<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en" level="a">Stiffness of Clays and Silts: Normalizing Shear Modulus and Shear Strain</title><author><name sortKey="Vardanega, P J" sort="Vardanega, P J" uniqKey="Vardanega P" first="P. J." last="Vardanega">P. J. Vardanega</name><affiliation wicri:level="1"><inist:fA14 i1="01"><s1>Dept. of Engineering, Univ. of Cambridge, Laing O'Rourke Centre for Construction Engineering and Technology</s1><s2>Cambridge CB2 1PZ</s2><s3>GBR</s3><sZ>1 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB2 1PZ</wicri:noRegion></affiliation></author><author><name sortKey="Bolton, M D" sort="Bolton, M D" uniqKey="Bolton M" first="M. D." last="Bolton">M. D. Bolton</name><affiliation wicri:level="1"><inist:fA14 i1="02"><s1>Dept. of Engineering, Univ. of Cambridge</s1><s2>Cambridge CB2 IPZ</s2><s3>GBR</s3><sZ>2 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB2 IPZ</wicri:noRegion></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">INIST</idno><idno type="inist">14-0018709</idno><date when="2013">2013</date><idno type="stanalyst">PASCAL 14-0018709 INIST</idno><idno type="RBID">Pascal:14-0018709</idno><idno type="wicri:Area/PascalFrancis/Corpus">000029</idno><idno type="wicri:Area/PascalFrancis/Curation">000735</idno><idno type="wicri:Area/PascalFrancis/Checkpoint">000028</idno><idno type="wicri:doubleKey">1090-0241:2013:Vardanega P:stiffness:of:clays</idno><idno type="wicri:Area/Main/Merge">000188</idno><idno type="wicri:Area/Main/Curation">000185</idno><idno type="wicri:Area/Main/Exploration">000185</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a">Stiffness of Clays and Silts: Normalizing Shear Modulus and Shear Strain</title><author><name sortKey="Vardanega, P J" sort="Vardanega, P J" uniqKey="Vardanega P" first="P. J." last="Vardanega">P. J. Vardanega</name><affiliation wicri:level="1"><inist:fA14 i1="01"><s1>Dept. of Engineering, Univ. of Cambridge, Laing O'Rourke Centre for Construction Engineering and Technology</s1><s2>Cambridge CB2 1PZ</s2><s3>GBR</s3><sZ>1 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB2 1PZ</wicri:noRegion></affiliation></author><author><name sortKey="Bolton, M D" sort="Bolton, M D" uniqKey="Bolton M" first="M. D." last="Bolton">M. D. Bolton</name><affiliation wicri:level="1"><inist:fA14 i1="02"><s1>Dept. of Engineering, Univ. of Cambridge</s1><s2>Cambridge CB2 IPZ</s2><s3>GBR</s3><sZ>2 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB2 IPZ</wicri:noRegion></affiliation></author></analytic><series><title level="j" type="main">Journal of geotechnical and geoenvironmental engineering</title><title level="j" type="abbreviated">J. geotech. geoenviron. eng.</title><idno type="ISSN">1090-0241</idno><imprint><date when="2013">2013</date></imprint></series></biblStruct></sourceDesc><seriesStmt><title level="j" type="main">Journal of geotechnical and geoenvironmental engineering</title><title level="j" type="abbreviated">J. geotech. geoenviron. eng.</title><idno type="ISSN">1090-0241</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Clay</term><term>Database</term><term>Degradation</term><term>Design</term><term>Dynamic characteristic</term><term>Forecast model</term><term>Property of soil</term><term>Shear</term><term>Silt</term><term>Soil test</term><term>Statistical analysis</term><term>Stiffness</term><term>Stress strain relation</term></keywords><keywords scheme="Pascal" xml:lang="fr"><term>Essai sol</term><term>Argile</term><term>Silt</term><term>Rigidité</term><term>Cisaillement</term><term>Relation contrainte déformation</term><term>Analyse statistique</term><term>Conception</term><term>Base de données</term><term>Caractéristique sol</term><term>Caractéristique dynamique</term><term>Modèle prévision</term><term>Dégradation</term></keywords><keywords scheme="Wicri" type="topic" xml:lang="fr"><term>Base de données</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">An analysis is presented of a database of 67 tests on 21 clays and silts of undrained shear stress-strain data of fine-grained soils. Normalizations of secant G in terms of initial mean effective stress p' (i.e., G/p' versus log γ) or undrained shear strength c<sub>u</sub> (i.e., G/c<sub>u</sub> versus log y) are shown to be much less successful in reducing the scatter between different clays than the approach that uses the maximum shear modulus, G<sub>max</sub>, a technique still not universally adopted by geotechnical researchers and constitutive modelers. Analysis of semiempirical expressions for G<sub>max</sub> is presented and a simple expression that uses only a void-ratio function and a confining-stress function is proposed. This is shown to be superior to a Hardin-style equation, and the void ratio function is demonstrated as an alternative to an overconsolidation ratio (OCR) function. To derive correlations that offer reliable estimates of secant stiffness at any required magnitude of working strain, secant shear modulus G is normalized with respect to its small-strain value G<sub>max</sub>, and shear strain γ is normalized with respect to a reference strain γ<sub>ref</sub> at which this stiffness has halved. The data are corrected to two standard strain rates to reduce the discrepancy between data obtained from static and cyclic testing. The reference strain γ<sub>ref</sub> is approximated as a function of the plasticity index. A unique normalized shear modulus reduction curve in the shape of a modified hyperbola is fitted to all the available data up to shear strains of the order of 1%. As a result, good estimates can be made of the modulus reduction G/G<sub>max</sub> ± 30% across all strain levels in approximately 90% of the cases studied. New design charts are proposed to update the commonly used design curves.</div></front></TEI><affiliations><list><country><li>Royaume-Uni</li></country></list><tree><country name="Royaume-Uni"><noRegion><name sortKey="Vardanega, P J" sort="Vardanega, P J" uniqKey="Vardanega P" first="P. J." last="Vardanega">P. J. Vardanega</name></noRegion><name sortKey="Bolton, M D" sort="Bolton, M D" uniqKey="Bolton M" first="M. D." last="Bolton">M. D. Bolton</name></country></tree></affiliations></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Ticri/CIDE/explor/OcrV1/Data/Main/Exploration
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 000185 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Main/Exploration/biblio.hfd -nk 000185 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Ticri/CIDE
|area= OcrV1
|flux= Main
|étape= Exploration
|type= RBID
|clé= Pascal:14-0018709
|texte= Stiffness of Clays and Silts: Normalizing Shear Modulus and Shear Strain
}}
| This area was generated with Dilib version V0.6.32. |  |