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Temperature-dependent internal friction of clay in a cylindrical heat source problem / T. Hueckel in Géotechnique, Vol. 61 N° 10 (Octobre 2010) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 10 (Octobre 2010) . - pp. 831-844 Titre : Temperature-dependent internal friction of clay in a cylindrical heat source problem Type de document : texte imprimé Auteurs : T. Hueckel, Auteur ; B. Francois, Auteur ; L. Laloui, Auteur Année de publication : 2011 Article en page(s) : pp. 831-844 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Friction  Temperature  effects  Numerical  modelling  Failure  Clays Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The effect of the temperature dependence of the internal friction angle is studied in a boundary value problem simulating the impact of a cylindrical heat source on the soil mass in which it is embedded. This follows a previous study which shows that such temperature dependence may substantially affect the interpretation of thermal failure in laboratory experiments. Even if the thermal increase of the internal friction is quite modest (less than 20% in terms of the critical state parameter, M), it affects quite significantly the effective stress path near the heat source. The effective stress path approaches the yield locus and the critical state at significantly higher principal stress difference values for the variable internal friction than for the M = const case. The ‘mean effective stress distance from the critical state' is substantially reduced during heating, which in the case of small perturbations of any parameter may lead to potentially unstable or statically inadmissible behaviour. The solutions obtained allow one to identify zones of influence around the heat source of several variables of interest. The two fields most affected by the thermal sensitivity of M are that of the axial stress, dropping significantly near the heat source, and that of the appearance of the thermoplastic strain. Both zones of influence are reduced in size by almost half when the friction angle is increased by 20% over 70°. The presented results may be of relevance to the design of prototype in situ installations and their monitoring, and eventually of actual facilities for nuclear waste disposal. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.124 [article] Temperature-dependent internal friction of clay in a cylindrical heat source problem [texte imprimé] / T. Hueckel, Auteur ; B. Francois, Auteur ; L. Laloui, Auteur . - 2011 . - pp. 831-844. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 10 (Octobre 2010) . - pp. 831-844 Mots-clés : Friction  Temperature  effects  Numerical  modelling  Failure  Clays Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The effect of the temperature dependence of the internal friction angle is studied in a boundary value problem simulating the impact of a cylindrical heat source on the soil mass in which it is embedded. This follows a previous study which shows that such temperature dependence may substantially affect the interpretation of thermal failure in laboratory experiments. Even if the thermal increase of the internal friction is quite modest (less than 20% in terms of the critical state parameter, M), it affects quite significantly the effective stress path near the heat source. The effective stress path approaches the yield locus and the critical state at significantly higher principal stress difference values for the variable internal friction than for the M = const case. The ‘mean effective stress distance from the critical state' is substantially reduced during heating, which in the case of small perturbations of any parameter may lead to potentially unstable or statically inadmissible behaviour. The solutions obtained allow one to identify zones of influence around the heat source of several variables of interest. The two fields most affected by the thermal sensitivity of M are that of the axial stress, dropping significantly near the heat source, and that of the appearance of the thermoplastic strain. Both zones of influence are reduced in size by almost half when the friction angle is increased by 20% over 70°. The presented results may be of relevance to the design of prototype in situ installations and their monitoring, and eventually of actual facilities for nuclear waste disposal. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.124