Documents disponibles écrits par cet auteur

Heating unsaturated medium sand / J. Ewen in Géotechnique, Vol. 39 N°3 (Septembre 1989) 

Public ISBD [article]  in Géotechnique > Vol. 39 N°3 (Septembre 1989) . - pp. 455 –470 Titre : Heating unsaturated medium sand Type de document : texte imprimé Auteurs : J. Ewen, Auteur ; H. R. Thomas, Auteur Année de publication : 2007 Article en page(s) : pp. 455 –470 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Partial  saturation  Temperature  Computation  Sands  Soil  properties Résumé : A theoretical, experimental and numerical investigation of combined heat and mass transfer in unsaturated sand is described. The theoretical formulation adopted is that of Philip & de Vries but slightly different forms of the vapour transfer dif-fusivities are developed. Experimental work is reported on the determination, for a medium sand, of the full set of material parameters incorporated in the formulation, using both methods developed by the Authors and standard techniques. Explicit equations are given for the capillary potential, unsaturated hydraulic conductivity and thermal conductivity as functions of moisture content and temperature. Laboratory experimental results are presented for the steady temperature distribution within an unsaturated sample of the sand in which a rod is buried and heated. The pattern of moisture content values achieved reveals a two region response, a dry zone surrounding the rod and wet sand elsewhere. The development of a numerical simulation of the heating experiment using a finite difference solution algorithm is described. A self implicit scheme, driven to steady state through a false transient, was employed. Good agreement was found between temperatures in the simulation and the experiment. The work described is unusual in that equal emphasis has been placed on experimentation, especially the determination of the soil's physical properties, and numerical modelling and the two-dimensional coupled partial differential equations describing combined heat and mass transfer have been solved without simplification. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/search?value1=%27soil+properties%27&option1=ful [...] [article] Heating unsaturated medium sand [texte imprimé] / J. Ewen, Auteur ; H. R. Thomas, Auteur . - 2007 . - pp. 455 –470. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 39 N°3 (Septembre 1989) . - pp. 455 –470 Mots-clés : Partial  saturation  Temperature  Computation  Sands  Soil  properties Résumé : A theoretical, experimental and numerical investigation of combined heat and mass transfer in unsaturated sand is described. The theoretical formulation adopted is that of Philip & de Vries but slightly different forms of the vapour transfer dif-fusivities are developed. Experimental work is reported on the determination, for a medium sand, of the full set of material parameters incorporated in the formulation, using both methods developed by the Authors and standard techniques. Explicit equations are given for the capillary potential, unsaturated hydraulic conductivity and thermal conductivity as functions of moisture content and temperature. Laboratory experimental results are presented for the steady temperature distribution within an unsaturated sample of the sand in which a rod is buried and heated. The pattern of moisture content values achieved reveals a two region response, a dry zone surrounding the rod and wet sand elsewhere. The development of a numerical simulation of the heating experiment using a finite difference solution algorithm is described. A self implicit scheme, driven to steady state through a false transient, was employed. Good agreement was found between temperatures in the simulation and the experiment. The work described is unusual in that equal emphasis has been placed on experimentation, especially the determination of the soil's physical properties, and numerical modelling and the two-dimensional coupled partial differential equations describing combined heat and mass transfer have been solved without simplification. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/search?value1=%27soil+properties%27&option1=ful [...]

Inclusion of some aspects of chemical behavior of unsaturated soil in thermo/hydro/chemical/mechanical models. I / P. J. Cleall in Journal of engineering mechanics, Vol. 133 N°3 (Mars 2007) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 133 N°3 (Mars 2007) . - pp.338–347. Titre : Inclusion of some aspects of chemical behavior of unsaturated soil in thermo/hydro/chemical/mechanical models. I : model development Type de document : texte imprimé Auteurs : P. J. Cleall, Auteur ; S. C. Seetharam, Auteur ; H. R. Thomas, Auteur Année de publication : 2007 Article en page(s) : pp.338–347. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Unsaturated  soils,  Numerical  models,  Soil  deformation,  Bentonite  Nuclear  wastes  Chemical  equilibrium  Transport  phenomena Résumé : This paper presents an investigation of the inclusion of some aspects of chemical behavior within a model of coupled thermo/hydro/chemical/mechanical behavior of unsaturated soils. In particular, multicomponent reactive chemical transport behavior is addressed. The chemical transport model is based on the advection/dispersion/reaction equation, while geochemical reactions are considered via coupling with an established geochemical speciation model. A numerical solution of the governing differential equations is achieved by the use of the Galerkin-weighted residual method for spatial discretization and an implicit backward Eulerian finite-difference method for temporal discretization. The solution of the geochemical reactions is achieved externally to the main solution procedure. Coupling between the chemical transport and geochemical models is achieved via the implementation of both sequential iterative and sequential noniterative techniques. Three application problems are then presented to demonstrate the capability of the coupled model. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A3%2833 [...] [article] Inclusion of some aspects of chemical behavior of unsaturated soil in thermo/hydro/chemical/mechanical models. I : model development [texte imprimé] / P. J. Cleall, Auteur ; S. C. Seetharam, Auteur ; H. R. Thomas, Auteur . - 2007 . - pp.338–347. Applied mechanics Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 133 N°3 (Mars 2007) . - pp.338–347. Mots-clés : Unsaturated  soils,  Numerical  models,  Soil  deformation,  Bentonite  Nuclear  wastes  Chemical  equilibrium  Transport  phenomena Résumé : This paper presents an investigation of the inclusion of some aspects of chemical behavior within a model of coupled thermo/hydro/chemical/mechanical behavior of unsaturated soils. In particular, multicomponent reactive chemical transport behavior is addressed. The chemical transport model is based on the advection/dispersion/reaction equation, while geochemical reactions are considered via coupling with an established geochemical speciation model. A numerical solution of the governing differential equations is achieved by the use of the Galerkin-weighted residual method for spatial discretization and an implicit backward Eulerian finite-difference method for temporal discretization. The solution of the geochemical reactions is achieved externally to the main solution procedure. Coupling between the chemical transport and geochemical models is achieved via the implementation of both sequential iterative and sequential noniterative techniques. Three application problems are then presented to demonstrate the capability of the coupled model. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A3%2833 [...]

Inclusion of some aspects of chemical behavior of unsaturated soil in thermo/hydro/chemical/mechanical models. II / P. J. Cleall in Journal of engineering mechanics, Vol. 133 N°3 (Mars 2007) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 133 N°3 (Mars 2007) . - pp.348–356. Titre : Inclusion of some aspects of chemical behavior of unsaturated soil in thermo/hydro/chemical/mechanical models. II : application and transport of soluble salts in compacted bentonite Type de document : texte imprimé Auteurs : P. J. Cleall, Auteur ; S. C. Seetharam, Auteur ; H. R. Thomas, Auteur Année de publication : 2007 Article en page(s) : pp.348–356. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Unsaturated  soils  Numerical  models  Soil  deformation  Nuclear  wastes  Chemical  equilibrium  Transport  phenomena Résumé : This paper presents an application of a coupled thermo/hydro/chemical/mechanical model via simulation of a laboratory experiment in order to investigate the transport behavior of ions in bentonite pore water. Chemical reactions considered include ion exchange reactions involving major cations ( Na+ , K+ , Mg2+ , and Ca2+ ) and precipitation-dissolution of trace minerals (calcite, dolomite, anhydrite, and halite). The following conclusions are drawn based on the numerical results. The development of both the temperature and moisture fields was captured by simulation, and a good correlation with the experimental water uptake results was observed. For all ions, the model showed a good qualitative and reasonable quantitative agreement with the experimental results. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A3%2834 [...] [article] Inclusion of some aspects of chemical behavior of unsaturated soil in thermo/hydro/chemical/mechanical models. II : application and transport of soluble salts in compacted bentonite [texte imprimé] / P. J. Cleall, Auteur ; S. C. Seetharam, Auteur ; H. R. Thomas, Auteur . - 2007 . - pp.348–356. Applied mechanics Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 133 N°3 (Mars 2007) . - pp.348–356. Mots-clés : Unsaturated  soils  Numerical  models  Soil  deformation  Nuclear  wastes  Chemical  equilibrium  Transport  phenomena Résumé : This paper presents an application of a coupled thermo/hydro/chemical/mechanical model via simulation of a laboratory experiment in order to investigate the transport behavior of ions in bentonite pore water. Chemical reactions considered include ion exchange reactions involving major cations ( Na+ , K+ , Mg2+ , and Ca2+ ) and precipitation-dissolution of trace minerals (calcite, dolomite, anhydrite, and halite). The following conclusions are drawn based on the numerical results. The development of both the temperature and moisture fields was captured by simulation, and a good correlation with the experimental water uptake results was observed. For all ions, the model showed a good qualitative and reasonable quantitative agreement with the experimental results. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A3%2834 [...]