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Analytical solution for biot flow–induced damping in saturated soil during shear wave excitations / Tong Qiu in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 11 (Novembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 11 (Novembre 2010) . - pp. 1501-1508 Titre : Analytical solution for biot flow–induced damping in saturated soil during shear wave excitations Type de document : texte imprimé Auteurs : Tong Qiu, Auteur Année de publication : 2011 Article en page(s) : pp. 1501-1508 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Vibration  Damping  Shear  wave  Wave  propagation  Hydraulic  conductivity  Coupling  Saturated  soils Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a theoretical study of Biot flow–induced damping in saturated soil during shear wave excitations. The solid skeleton is treated as equivalent linear. Biot flow–induced damping is evaluated for the cases of resonant column tests and site response analysis, based on the spectral response of a soil column/layer under harmonic torsional/horizontal excitations. Closed-form analytical solutions indicate that Biot flow–induced damping is hydraulic conductivity and frequency dependant. At the first resonance in a resonant column test, Biot flow–induced damping is dependent on a dimensionless hydraulic conductivity parameter K. For K within the range of 0.01 to 100, corresponding to coarse sands and clean gravels, Biot flow–induced damping may have an important contribution to total soil damping, especially at small strain levels. For site response analysis, Biot flow–induced damping should be considered for coarse sands and clean gravels, but can be practically neglected for fine sands, silts, and clays. The effects of soil porosity, mass coupling, and non-Poiseuille flow on Biot flow–induced damping are discussed. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&ONLINE=YES&s [...] [article] Analytical solution for biot flow–induced damping in saturated soil during shear wave excitations [texte imprimé] / Tong Qiu, Auteur . - 2011 . - pp. 1501-1508. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 11 (Novembre 2010) . - pp. 1501-1508 Mots-clés : Vibration  Damping  Shear  wave  Wave  propagation  Hydraulic  conductivity  Coupling  Saturated  soils Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a theoretical study of Biot flow–induced damping in saturated soil during shear wave excitations. The solid skeleton is treated as equivalent linear. Biot flow–induced damping is evaluated for the cases of resonant column tests and site response analysis, based on the spectral response of a soil column/layer under harmonic torsional/horizontal excitations. Closed-form analytical solutions indicate that Biot flow–induced damping is hydraulic conductivity and frequency dependant. At the first resonance in a resonant column test, Biot flow–induced damping is dependent on a dimensionless hydraulic conductivity parameter K. For K within the range of 0.01 to 100, corresponding to coarse sands and clean gravels, Biot flow–induced damping may have an important contribution to total soil damping, especially at small strain levels. For site response analysis, Biot flow–induced damping should be considered for coarse sands and clean gravels, but can be practically neglected for fine sands, silts, and clays. The effects of soil porosity, mass coupling, and non-Poiseuille flow on Biot flow–induced damping are discussed. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&ONLINE=YES&s [...]

Effective soil density for propagation of small strain shear waves in saturated soil / Tong Qiu in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°12 (Décembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°12 (Décembre 2008) . - pp. 1815–1819 Titre : Effective soil density for propagation of small strain shear waves in saturated soil Type de document : texte imprimé Auteurs : Tong Qiu, Auteur ; Fox, Patrick J., Auteur Année de publication : 2009 Article en page(s) : pp. 1815–1819 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil  properties  Density  Saturated  soils  Shear  modulus  Wave  velocity  Hydraulic  conductivity  Wave  propagation Résumé : This technical note defines an “effective soil density” that controls the velocity of small strain shear waves in saturated soil. Biot theory indicates that the ratio of effective density to saturated density will generally range from 0.75 to 1.0 and is a function of specific gravity of solids, porosity, hydraulic conductivity, and shear wave frequency. For many geotechnical applications, effective density will be equal to saturated density for low hydraulic conductivity soils (clays and silts) and may be less than saturated density for high hydraulic conductivity soils (clean sands and gravels). The findings are relevant to applications involving the propagation of small strain shear waves through saturated soil, and in particular for laboratory and field tests in which shear modulus is back-calculated from measured shear-wave velocity. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A12%281 [...] [article] Effective soil density for propagation of small strain shear waves in saturated soil [texte imprimé] / Tong Qiu, Auteur ; Fox, Patrick J., Auteur . - 2009 . - pp. 1815–1819. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°12 (Décembre 2008) . - pp. 1815–1819 Mots-clés : Soil  properties  Density  Saturated  soils  Shear  modulus  Wave  velocity  Hydraulic  conductivity  Wave  propagation Résumé : This technical note defines an “effective soil density” that controls the velocity of small strain shear waves in saturated soil. Biot theory indicates that the ratio of effective density to saturated density will generally range from 0.75 to 1.0 and is a function of specific gravity of solids, porosity, hydraulic conductivity, and shear wave frequency. For many geotechnical applications, effective density will be equal to saturated density for low hydraulic conductivity soils (clays and silts) and may be less than saturated density for high hydraulic conductivity soils (clean sands and gravels). The findings are relevant to applications involving the propagation of small strain shear waves through saturated soil, and in particular for laboratory and field tests in which shear modulus is back-calculated from measured shear-wave velocity. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A12%281 [...]

Energy dissipation in nearly saturated poroviscoelastic soil columns during quasi-static compressional excitations / Tong Qiu in Journal of engineering mechanics, Vol. 138 N° 10 (Octobre 2012) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 138 N° 10 (Octobre 2012) . - pp.1263–1274. Titre : Energy dissipation in nearly saturated poroviscoelastic soil columns during quasi-static compressional excitations Type de document : texte imprimé Auteurs : Tong Qiu, Auteur ; Yanbo Huang, Auteur Année de publication : 2012 Article en page(s) : pp.1263–1274. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Compression  Coupling  Damping  Excitation  Relaxation  Saturated  soils  Vibration  Viscoelasticity Résumé : This paper presents a theoretical investigation on the energy dissipation in a nearly saturated poroviscoelastic soil column under quasi-static compressional excitations. Different components of the energy dissipation are evaluated and compared. The magnitude of fluid- induced energy dissipation is primarily a function of a normalized excitation frequency Ω. For small values of Ω, a drained soil column is fully relaxed and essentially behaves as a dry column with negligible pore pressure. For such a soil column, fluid-induced energy dissipation is negligible, and the total damping ratio of the column is essentially the same as that of the solid skeleton. For very high values of Ω, a drained soil column is fully loaded and the excitation-generated pore pressure decreases as the fluid becomes more compressible. For such a soil column, the fluid pressure gradient only exists in a thin boundary layer near the drainage boundary, where drainage occurs and fluid induces energy dissipation, whereas the rest of the column is essentially undrained. Significant fluid-induced energy dissipation occurs for moderate values of Ω because of a combination of moderate fluid pressure, pressure gradient, and fluid relative motion throughout the soil column. The effects of the boundary drainage condition, saturation, porosity, and skeleton damping ratio on fluid-induced energy dissipation are discussed. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000428 [article] Energy dissipation in nearly saturated poroviscoelastic soil columns during quasi-static compressional excitations [texte imprimé] / Tong Qiu, Auteur ; Yanbo Huang, Auteur . - 2012 . - pp.1263–1274. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 138 N° 10 (Octobre 2012) . - pp.1263–1274. Mots-clés : Compression  Coupling  Damping  Excitation  Relaxation  Saturated  soils  Vibration  Viscoelasticity Résumé : This paper presents a theoretical investigation on the energy dissipation in a nearly saturated poroviscoelastic soil column under quasi-static compressional excitations. Different components of the energy dissipation are evaluated and compared. The magnitude of fluid- induced energy dissipation is primarily a function of a normalized excitation frequency Ω. For small values of Ω, a drained soil column is fully relaxed and essentially behaves as a dry column with negligible pore pressure. For such a soil column, fluid-induced energy dissipation is negligible, and the total damping ratio of the column is essentially the same as that of the solid skeleton. For very high values of Ω, a drained soil column is fully loaded and the excitation-generated pore pressure decreases as the fluid becomes more compressible. For such a soil column, the fluid pressure gradient only exists in a thin boundary layer near the drainage boundary, where drainage occurs and fluid induces energy dissipation, whereas the rest of the column is essentially undrained. Significant fluid-induced energy dissipation occurs for moderate values of Ω because of a combination of moderate fluid pressure, pressure gradient, and fluid relative motion throughout the soil column. The effects of the boundary drainage condition, saturation, porosity, and skeleton damping ratio on fluid-induced energy dissipation are discussed. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000428

Hydraulic Damping of Saturated Poroelestic Soils During Steady-State-State Vibration / Tong Qiu in Journal of engineering mechanics, V ol. 132 N°8 (Août 2006) 

Public ISBD [article]  in Journal of engineering mechanics > V ol. 132 N°8 (Août 2006) . - 859-870 p. Titre : Hydraulic Damping of Saturated Poroelestic Soils During Steady-State-State Vibration Titre original : Atténuation Hydraulique des Sols saturés de Poro-elesticue Pendant la Vibration d'Etat d'Equilibre Type de document : texte imprimé Auteurs : Tong Qiu, Auteur ; Abousleiman, Younane, Editeur scientifique ; Fox, Patrick J., Auteur Article en page(s) : 859-870 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Porous  media  Saturated  soils  Damping  Coupling  Soil  dynamics  Vibration  Poro-elasticity  Médias  poreux  Sols  saturés  Atténuation  Accouplement  Dynamique  de  sol  Poro-élasticité Index. décimale : 621.3 Ingénierie électrique Résumé : A theoretical study of the steady-state response of a saturated poroelastic soil column during compressional and rotational harmonic vibrations is presented. Hydraulic damping due to Biot flow is evaluated for top-drained and double-drained boundary conditions and for compressional and rotational motions using the theory of a damped single-degree-of-freedom system. For compressional motions, the dynamic response of gravels and sands is highly influenced by the compressibility of the pore fluid. More hydraulic damping occurs as soil hydraulic conductivity increases and as the column boundary conditions change from top drained to double drained. On the other hand, hydraulic damping for rotational motions is significantly less than that for compressional motions and is dependent on a dimensionless hydraulic conductivity parameter Ks. For Ks within the range of 10-3-100, hydraulic damping may have an important contribution to total soil damping, especially at small strain levels. Une étude théorique de la réponse d'état d'équilibre d'une colonne poroelastic saturée de sol pendant des vibrations harmoniques de compression et de rotation est présentée. L'atténuation hydraulique due à l'écoulement de Biot est évaluée pour des états vidangés vidangés et doubles de dessus de frontière et pour des mouvements de compression et de rotation en utilisant la théorie d'un seul degré atténué de système de liberté. Pour des mouvements de compression, la réponse dynamique des graviers et des sables est fortement influencée par la compressibilité du fluide de pore. Une atténuation plus hydraulique se produit pendant que des augmentations hydrauliques de conductivité de sol et pendant que les conditions de frontière de colonne changent du dessus vidangé en le double vidangé. D'autre part, l'atténuation hydraulique pour des mouvements de rotation est de manière significative moins que cela pour des mouvements de compression et dépend d'un paramètre hydraulique sans dimensions K?s de conductivité ?. Pour K?s ? dans la marge de 10?-3?-100, l'atténuation hydraulique peut avoir une contribution importante pour se monter au sol atténuant, particulièrement à la petite contrainte nivelle. En ligne : qiutong@ucla.edu, fox.407@osu.edu [article] Hydraulic Damping of Saturated Poroelestic Soils During Steady-State-State Vibration = Atténuation Hydraulique des Sols saturés de Poro-elesticue Pendant la Vibration d'Etat d'Equilibre [texte imprimé] / Tong Qiu, Auteur ; Abousleiman, Younane, Editeur scientifique ; Fox, Patrick J., Auteur . - 859-870 p. Génie Mécanique Langues : Anglais (eng) in Journal of engineering mechanics > V ol. 132 N°8 (Août 2006) . - 859-870 p. Mots-clés : Porous  media  Saturated  soils  Damping  Coupling  Soil  dynamics  Vibration  Poro-elasticity  Médias  poreux  Sols  saturés  Atténuation  Accouplement  Dynamique  de  sol  Poro-élasticité Index. décimale : 621.3 Ingénierie électrique Résumé : A theoretical study of the steady-state response of a saturated poroelastic soil column during compressional and rotational harmonic vibrations is presented. Hydraulic damping due to Biot flow is evaluated for top-drained and double-drained boundary conditions and for compressional and rotational motions using the theory of a damped single-degree-of-freedom system. For compressional motions, the dynamic response of gravels and sands is highly influenced by the compressibility of the pore fluid. More hydraulic damping occurs as soil hydraulic conductivity increases and as the column boundary conditions change from top drained to double drained. On the other hand, hydraulic damping for rotational motions is significantly less than that for compressional motions and is dependent on a dimensionless hydraulic conductivity parameter Ks. For Ks within the range of 10-3-100, hydraulic damping may have an important contribution to total soil damping, especially at small strain levels. Une étude théorique de la réponse d'état d'équilibre d'une colonne poroelastic saturée de sol pendant des vibrations harmoniques de compression et de rotation est présentée. L'atténuation hydraulique due à l'écoulement de Biot est évaluée pour des états vidangés vidangés et doubles de dessus de frontière et pour des mouvements de compression et de rotation en utilisant la théorie d'un seul degré atténué de système de liberté. Pour des mouvements de compression, la réponse dynamique des graviers et des sables est fortement influencée par la compressibilité du fluide de pore. Une atténuation plus hydraulique se produit pendant que des augmentations hydrauliques de conductivité de sol et pendant que les conditions de frontière de colonne changent du dessus vidangé en le double vidangé. D'autre part, l'atténuation hydraulique pour des mouvements de rotation est de manière significative moins que cela pour des mouvements de compression et dépend d'un paramètre hydraulique sans dimensions K?s de conductivité ?. Pour K?s ? dans la marge de 10?-3?-100, l'atténuation hydraulique peut avoir une contribution importante pour se monter au sol atténuant, particulièrement à la petite contrainte nivelle. En ligne : qiutong@ucla.edu, fox.407@osu.edu