Documents disponibles écrits par cet auteur

Consolidation of a Finite Transversely Isotropic Soil Layer on a Rough Impervious Base / S. L. Chen in Journal of engineering mechanics, Vol. 131, N°12 (Decembre 2005) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 131, N°12 (Decembre 2005) . - 1279-1290 p. Titre : Consolidation of a Finite Transversely Isotropic Soil Layer on a Rough Impervious Base Titre original : Consolidation d'une Couche Transversalement Isotrope Finie de Sol sur une Base Imperméable Approximative Type de document : texte imprimé Auteurs : S. L. Chen, Auteur ; Zhang, L. M., Editeur scientifique ; L. Z. Chen ; Cheng, Alexander H.-D. Article en page(s) : 1279-1290 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Soil  consolidation  Isotropy  Layered  soil  Integrals  Consolidation  de  sol  Isotropie  Sol  posé  Intégrales Index. décimale : 621.34 Résumé : A semianalytical solution to axisymmetric consolidation of a transversely isotropic soil layer resting on a rough impervious base and subjected to a uniform circular pressure at the ground surface is presented. The Analysis uses Biot's fully coupled consolidation theory for a transversely isotropic soil. The General solutions are the governing consolidation equations are derived by applying the Hankel and Laplace transform tehniques. These General solutions are then used to solve the corresponding boundary value problem for the consolidation of the transversely isotropic soil layer. Once solutions in the transformed domain have been found, the actual solutions in the physical domain for displacements and stress components of the solid matrix, pore-water pressure and fluid discharge can finally be obtained by direct numerical inversions of the integral transforms. The Accuracy of the present numerical solutions is confirmed by comparison with an existing exact solutions for an isotropic and saturated soil that is a special case of the more general problem addressed. Further, some numerical results are presented to show the influence of the nature of material anistropy, the surface drainage conditions, and the layer thickness on the consolidation settlement and the pore pressure dissipation. Une solution analytique de semi-finale à la consolidation axisymmetrique d'une couche transversalement isotrope de sol se reposant sur une base imperméable approximative et soumise à une pression circulaire uniforme sur la surface au sol est présentée. L'analyse emploie la théorie entièrement couplée de la consolidation de Biot pour un sol transversalement isotrope. Les solutions générales sont les équations régissantes de consolidation sont dérivées en appliquant le Hankel et Laplace transforment des tehniques. Ces solutions générales sont alors employées pour résoudre le problème de valeur correspondant pour la consolidation de la couche transversalement isotrope de sol. Une fois des solutions dans le domaine transformé ont été trouvées, les solutions réelles dans le domaine physique pour des déplacements et des composants d'effort de la matrice, de la pression de l'pore-eau et de la décharge pleines de fluide peuvent finalement être obtenus par des inversions numériques directes de l'intégrale transforme. L'exactitude des solutions numériques actuelles est confirmée par comparaison avec les solutions exactes existantes pour un sol isotrope et saturé qui est un cas spécial du problème plus général adressé. De plus, quelques résultats numériques sont présentés pour montrer l'influence de la nature d'anistropie matériel, des conditions extérieurs de drainage, et de l'épaisseur de couche sur le règlement de consolidation et la dissipation de pression de pore. En ligne : sheng_chen@sjtu.edu.cn, cezhangl@ust.hk, 1zchen@sjtu.edu.cn [article] Consolidation of a Finite Transversely Isotropic Soil Layer on a Rough Impervious Base = Consolidation d'une Couche Transversalement Isotrope Finie de Sol sur une Base Imperméable Approximative [texte imprimé] / S. L. Chen, Auteur ; Zhang, L. M., Editeur scientifique ; L. Z. Chen ; Cheng, Alexander H.-D. . - 1279-1290 p. Génie Mécanique Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 131, N°12 (Decembre 2005) . - 1279-1290 p. Mots-clés : Soil  consolidation  Isotropy  Layered  soil  Integrals  Consolidation  de  sol  Isotropie  Sol  posé  Intégrales Index. décimale : 621.34 Résumé : A semianalytical solution to axisymmetric consolidation of a transversely isotropic soil layer resting on a rough impervious base and subjected to a uniform circular pressure at the ground surface is presented. The Analysis uses Biot's fully coupled consolidation theory for a transversely isotropic soil. The General solutions are the governing consolidation equations are derived by applying the Hankel and Laplace transform tehniques. These General solutions are then used to solve the corresponding boundary value problem for the consolidation of the transversely isotropic soil layer. Once solutions in the transformed domain have been found, the actual solutions in the physical domain for displacements and stress components of the solid matrix, pore-water pressure and fluid discharge can finally be obtained by direct numerical inversions of the integral transforms. The Accuracy of the present numerical solutions is confirmed by comparison with an existing exact solutions for an isotropic and saturated soil that is a special case of the more general problem addressed. Further, some numerical results are presented to show the influence of the nature of material anistropy, the surface drainage conditions, and the layer thickness on the consolidation settlement and the pore pressure dissipation. Une solution analytique de semi-finale à la consolidation axisymmetrique d'une couche transversalement isotrope de sol se reposant sur une base imperméable approximative et soumise à une pression circulaire uniforme sur la surface au sol est présentée. L'analyse emploie la théorie entièrement couplée de la consolidation de Biot pour un sol transversalement isotrope. Les solutions générales sont les équations régissantes de consolidation sont dérivées en appliquant le Hankel et Laplace transforment des tehniques. Ces solutions générales sont alors employées pour résoudre le problème de valeur correspondant pour la consolidation de la couche transversalement isotrope de sol. Une fois des solutions dans le domaine transformé ont été trouvées, les solutions réelles dans le domaine physique pour des déplacements et des composants d'effort de la matrice, de la pression de l'pore-eau et de la décharge pleines de fluide peuvent finalement être obtenus par des inversions numériques directes de l'intégrale transforme. L'exactitude des solutions numériques actuelles est confirmée par comparaison avec les solutions exactes existantes pour un sol isotrope et saturé qui est un cas spécial du problème plus général adressé. De plus, quelques résultats numériques sont présentés pour montrer l'influence de la nature d'anistropie matériel, des conditions extérieurs de drainage, et de l'épaisseur de couche sur le règlement de consolidation et la dissipation de pression de pore. En ligne : sheng_chen@sjtu.edu.cn, cezhangl@ust.hk, 1zchen@sjtu.edu.cn

Exact undrained elasto-plastic solution for cylindrical cavity expansion in modified Cam Clay soil / S. L. Chen in Géotechnique, Vol. 62 N° 5 (Mai 2012) 

Public ISBD [article]  in Géotechnique > Vol. 62 N° 5 (Mai 2012) . - pp. 447 –456 Titre : Exact undrained elasto-plastic solution for cylindrical cavity expansion in modified Cam Clay soil Type de document : texte imprimé Auteurs : S. L. Chen, Auteur ; Y. N. Abousleiman, Auteur Année de publication : 2012 Article en page(s) : pp. 447 –456 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Theoretical  analysis  Pore  pressure  Stress  path  Plasticity  Stress  analysis  In  situ  testing Résumé : This paper presents an exact semi-analytical analysis for cylindrical cavity expansion in modified Cam Clay critical state soil under the undrained condition. By assuming small-strain deformation in the elastic region and large-strain deformation in the plastic region, the formulation of the problem is reduced to solving a system of first-order ordinary differential equations for the radial, tangential and vertical effective stresses in the plastic zone. The pore pressure distribution can subsequently be determined from the radial equilibrium equation in terms of the total stresses. The semi-analytical solution derived in this paper follows the rigorous definitions for the two effective stress invariants instead of approximate ones, as usually assumed in the existing literature, and applies to the more general case where the out-of-plane (vertical) in situ stress may be different from the in-plane (horizontal) one. The results show clearly that the stress history (overconsolidation ratio) has a significant influence on the stress and pore pressure distributions around the cavity. The present solution provides an exact and realistic theoretical framework for predicting the soil behaviour around the cylindrical cavity, with applications to the interpretation of pressuremeter tests and to pile installation problems. It also serves as a valuable benchmark for verifying various cavity expansion numerical methods involving the critical state plasticity model. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.11.P.027 [article] Exact undrained elasto-plastic solution for cylindrical cavity expansion in modified Cam Clay soil [texte imprimé] / S. L. Chen, Auteur ; Y. N. Abousleiman, Auteur . - 2012 . - pp. 447 –456. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 62 N° 5 (Mai 2012) . - pp. 447 –456 Mots-clés : Theoretical  analysis  Pore  pressure  Stress  path  Plasticity  Stress  analysis  In  situ  testing Résumé : This paper presents an exact semi-analytical analysis for cylindrical cavity expansion in modified Cam Clay critical state soil under the undrained condition. By assuming small-strain deformation in the elastic region and large-strain deformation in the plastic region, the formulation of the problem is reduced to solving a system of first-order ordinary differential equations for the radial, tangential and vertical effective stresses in the plastic zone. The pore pressure distribution can subsequently be determined from the radial equilibrium equation in terms of the total stresses. The semi-analytical solution derived in this paper follows the rigorous definitions for the two effective stress invariants instead of approximate ones, as usually assumed in the existing literature, and applies to the more general case where the out-of-plane (vertical) in situ stress may be different from the in-plane (horizontal) one. The results show clearly that the stress history (overconsolidation ratio) has a significant influence on the stress and pore pressure distributions around the cavity. The present solution provides an exact and realistic theoretical framework for predicting the soil behaviour around the cylindrical cavity, with applications to the interpretation of pressuremeter tests and to pile installation problems. It also serves as a valuable benchmark for verifying various cavity expansion numerical methods involving the critical state plasticity model. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.11.P.027

Note on the interaction factor for two laterally loaded piles / S. L. Chen 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. 1685–1690 Titre : Note on the interaction factor for two laterally loaded piles Type de document : texte imprimé Auteurs : S. L. Chen, Auteur ; L. Z. Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 1685–1690 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Piles  Lateral  loads  Bending  moments  Interactions Résumé : This technical note revisits the interaction factors for two piles under lateral loading by means of a rigorous analytical method. The basic idea of the approach presented is to decompose the problem into an extended elastic soil and two fictitious piles having Young’s modulus equal to the difference between the modulus of the real pile and the surrounding soil. By considering the displacement compatibility condition, the pile–soil interaction problem is found to be governed by a Fredholm equation of the second kind. The displacement and bending moment distribution along the fictitious piles, and consequently, the desired interaction factor at the pile head are obtained. Comparison with existing solutions validates the accuracy of the present formulation and confirms that the conventional interaction factor approach would exaggerate the interaction effect for long flexible piles. Some numerical examples are presented to illustrate the influences of the pile spacing, pile–soil stiffness ratio, pile slenderness ratio, and departure angle of the loading direction on the calculated results. A set of interaction factor charts is also provided. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Note on the interaction factor for two laterally loaded piles [texte imprimé] / S. L. Chen, Auteur ; L. Z. Chen, Auteur . - 2009 . - pp. 1685–1690. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1685–1690 Mots-clés : Piles  Lateral  loads  Bending  moments  Interactions Résumé : This technical note revisits the interaction factors for two piles under lateral loading by means of a rigorous analytical method. The basic idea of the approach presented is to decompose the problem into an extended elastic soil and two fictitious piles having Young’s modulus equal to the difference between the modulus of the real pile and the surrounding soil. By considering the displacement compatibility condition, the pile–soil interaction problem is found to be governed by a Fredholm equation of the second kind. The displacement and bending moment distribution along the fictitious piles, and consequently, the desired interaction factor at the pile head are obtained. Comparison with existing solutions validates the accuracy of the present formulation and confirms that the conventional interaction factor approach would exaggerate the interaction effect for long flexible piles. Some numerical examples are presented to illustrate the influences of the pile spacing, pile–soil stiffness ratio, pile slenderness ratio, and departure angle of the loading direction on the calculated results. A set of interaction factor charts is also provided. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

A ternary phase-field model incorporating commercial CALPHAD software and its application to precipitation in superalloys / Y. H. Wen in Acta materialia, Vol. 58 N° 3 (Fevrier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 3 (Fevrier 2010) . - pp. 875-885 Titre : A ternary phase-field model incorporating commercial CALPHAD software and its application to precipitation in superalloys Type de document : texte imprimé Auteurs : Y. H. Wen, Auteur ; J. V. Lill, Auteur ; S. L. Chen, Auteur Article en page(s) : pp. 875-885 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Ni–Al–Cr  alloys  Ternary  phase-field  models  Precipitation  Commercial  CALPHAD  software  Uphill  diffusion Index. décimale : 669 Métallurgie Résumé : A ternary phase-field model was developed that is linked directly to commercial CALPHAD software to provide quantitative thermodynamic driving forces. A recently available diffusion mobility database for ordered phases is also implemented to give a better description of the diffusion behavior in alloys. Because the targeted application of this model is the study of precipitation in Ni-based superalloys, a Ni–Al–Cr model alloy was constructed. A detailed description of this model is given in the paper. We have considered the misfit effects of the partitioning of the two solute elements. Transformation rules of the dual representation of the γ+γ′ microstructure by CALPHAD and by the phase field are established and the link with commercial CALPHAD software is described. Proof-of-concept tests were performed to evaluate the model and the results demonstrate that the model can qualitatively reproduce observed γ′ precipitation behavior. Uphill diffusion of Al is observed in a few diffusion couples, showing the significant influence of Cr on the chemical potential of Al. Possible applications of this model are discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...] [article] A ternary phase-field model incorporating commercial CALPHAD software and its application to precipitation in superalloys [texte imprimé] / Y. H. Wen, Auteur ; J. V. Lill, Auteur ; S. L. Chen, Auteur . - pp. 875-885. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 3 (Fevrier 2010) . - pp. 875-885 Mots-clés : Ni–Al–Cr  alloys  Ternary  phase-field  models  Precipitation  Commercial  CALPHAD  software  Uphill  diffusion Index. décimale : 669 Métallurgie Résumé : A ternary phase-field model was developed that is linked directly to commercial CALPHAD software to provide quantitative thermodynamic driving forces. A recently available diffusion mobility database for ordered phases is also implemented to give a better description of the diffusion behavior in alloys. Because the targeted application of this model is the study of precipitation in Ni-based superalloys, a Ni–Al–Cr model alloy was constructed. A detailed description of this model is given in the paper. We have considered the misfit effects of the partitioning of the two solute elements. Transformation rules of the dual representation of the γ+γ′ microstructure by CALPHAD and by the phase field are established and the link with commercial CALPHAD software is described. Proof-of-concept tests were performed to evaluate the model and the results demonstrate that the model can qualitatively reproduce observed γ′ precipitation behavior. Uphill diffusion of Al is observed in a few diffusion couples, showing the significant influence of Cr on the chemical potential of Al. Possible applications of this model are discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...]

A ternary phase-field model incorporating commercial CALPHAD software and its application to precipitation in superalloys / Y. H. Wen in Acta materialia, Vol. 58 N° 3 (Fevrier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 3 (Fevrier 2010) . - pp. 875–885 Titre : A ternary phase-field model incorporating commercial CALPHAD software and its application to precipitation in superalloys Type de document : texte imprimé Auteurs : Y. H. Wen, Auteur ; J. V. Lill, Auteur ; S. L. Chen, Auteur Année de publication : 2011 Article en page(s) : pp. 875–885 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Ni–Al–Cr  alloys  Ternary  phase-field  models  Precipitation  Commercial  CALPHAD  software  Uphill  diffusion Résumé : A ternary phase-field model was developed that is linked directly to commercial CALPHAD software to provide quantitative thermodynamic driving forces. A recently available diffusion mobility database for ordered phases is also implemented to give a better description of the diffusion behavior in alloys. Because the targeted application of this model is the study of precipitation in Ni-based superalloys, a Ni–Al–Cr model alloy was constructed. A detailed description of this model is given in the paper. We have considered the misfit effects of the partitioning of the two solute elements. Transformation rules of the dual representation of the γ+γ′ microstructure by CALPHAD and by the phase field are established and the link with commercial CALPHAD software is described. Proof-of-concept tests were performed to evaluate the model and the results demonstrate that the model can qualitatively reproduce observed γ′ precipitation behavior. Uphill diffusion of Al is observed in a few diffusion couples, showing the significant influence of Cr on the chemical potential of Al. Possible applications of this model are discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409006818 [article] A ternary phase-field model incorporating commercial CALPHAD software and its application to precipitation in superalloys [texte imprimé] / Y. H. Wen, Auteur ; J. V. Lill, Auteur ; S. L. Chen, Auteur . - 2011 . - pp. 875–885. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 3 (Fevrier 2010) . - pp. 875–885 Mots-clés : Ni–Al–Cr  alloys  Ternary  phase-field  models  Precipitation  Commercial  CALPHAD  software  Uphill  diffusion Résumé : A ternary phase-field model was developed that is linked directly to commercial CALPHAD software to provide quantitative thermodynamic driving forces. A recently available diffusion mobility database for ordered phases is also implemented to give a better description of the diffusion behavior in alloys. Because the targeted application of this model is the study of precipitation in Ni-based superalloys, a Ni–Al–Cr model alloy was constructed. A detailed description of this model is given in the paper. We have considered the misfit effects of the partitioning of the two solute elements. Transformation rules of the dual representation of the γ+γ′ microstructure by CALPHAD and by the phase field are established and the link with commercial CALPHAD software is described. Proof-of-concept tests were performed to evaluate the model and the results demonstrate that the model can qualitatively reproduce observed γ′ precipitation behavior. Uphill diffusion of Al is observed in a few diffusion couples, showing the significant influence of Cr on the chemical potential of Al. Possible applications of this model are discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409006818

Vertical vibration of a flexible plate with rigid core on saturated ground / S. L. Chen in Journal of engineering mechanics, Vol. 133 N°3 (Mars 2007) 

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