Documents disponibles écrits par cet auteur

Cone penetration tests in a virtual calibration chamber / M. Arroyo in Géotechnique, Vol. 61 N° 6 (Juin 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 6 (Juin 2011) . - pp. 525–531 Titre : Cone penetration tests in a virtual calibration chamber Type de document : texte imprimé Auteurs : M. Arroyo, Auteur ; J. Butlanska, Auteur ; A. Gens, Auteur Année de publication : 2011 Article en page(s) : pp. 525–531 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Sands  Laboratory  testing  In  Situ  testing  Numerical  modelling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A virtual calibration chamber was built using a three-dimensional model based on the discrete-element method. The chamber was then filled with a scaled granular equivalent of Ticino sand, the material properties of which were selected by curve-fitting triaxial tests. Cone penetration tests were then performed under different initial densities and isotropic stresses. Penetration resistance in the virtual calibration chamber was affected by the same cone/chamber size effect that affects physical calibration chambers and was corrected accordingly. The corrected cone resistance obtained from the virtual calibration chamber cone penetration tests shows good quantitative agreement with correlations that summarise previous physical results. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.067 [article] Cone penetration tests in a virtual calibration chamber [texte imprimé] / M. Arroyo, Auteur ; J. Butlanska, Auteur ; A. Gens, Auteur . - 2011 . - pp. 525–531. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 6 (Juin 2011) . - pp. 525–531 Mots-clés : Sands  Laboratory  testing  In  Situ  testing  Numerical  modelling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A virtual calibration chamber was built using a three-dimensional model based on the discrete-element method. The chamber was then filled with a scaled granular equivalent of Ticino sand, the material properties of which were selected by curve-fitting triaxial tests. Cone penetration tests were then performed under different initial densities and isotropic stresses. Penetration resistance in the virtual calibration chamber was affected by the same cone/chamber size effect that affects physical calibration chambers and was corrected accordingly. The corrected cone resistance obtained from the virtual calibration chamber cone penetration tests shows good quantitative agreement with correlations that summarise previous physical results. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.067

Drained principal stress rotation in saturated sand / M. J. Symes in Géotechnique, Vol. 39 N°3 (Septembre 1989) 

Public ISBD [article]  in Géotechnique > Vol. 39 N°3 (Septembre 1989) . - pp. 549 –552 Titre : Drained principal stress rotation in saturated sand Type de document : texte imprimé Auteurs : M. J. Symes, Auteur ; A. Gens, Auteur ; D. W. Hight, Auteur Année de publication : 2007 Article en page(s) : pp. 549 –552 Note générale : Génie Civil Langues : Anglais (eng) Note de contenu : Discussion ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.3.549 [article] Drained principal stress rotation in saturated sand [texte imprimé] / M. J. Symes, Auteur ; A. Gens, Auteur ; D. W. Hight, Auteur . - 2007 . - pp. 549 –552. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 39 N°3 (Septembre 1989) . - pp. 549 –552 Note de contenu : Discussion ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.3.549

Hydromechanical behaviour of a heterogeneous compacted soil: experimental observations and modelling / A. Gens in Géotechnique, Vol. 61 N° 5 (Mai 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 5 (Mai 2011) . - pp. 367–386 Titre : Hydromechanical behaviour of a heterogeneous compacted soil: experimental observations and modelling Type de document : texte imprimé Auteurs : A. Gens, Auteur ; B. Vallejan, Auteur ; M. Sanchez, Auteur Année de publication : 2011 Article en page(s) : pp. 367–386 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Laboratory  tests  Fabric/Structure  of  soils  Compaction  Partial  saturation  Expansive  soils  Full-scale  tests Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The paper describes a theoretical and experimental study of the coupled hydromechanical behaviour of a compacted mixture of bentonite powder and bentonite pellets intended as sealing material in underground repositories for nuclear waste. One of the main advantages of the use of powder/pellets mixtures is the reduction of the compaction effort required to achieve the value of average dry density necessary to attain the required swelling potential. However, the heterogeneous fabric of the material requires special approaches in order to describe adequately its behaviour during hydration. A double porosity formulation is presented to account for the presence of two distinct structural levels in the material. Hydraulic equilibrium between the two porosities is not assumed; instead a water exchange term between them is postulated. The formulation is applied to the modelling of a number of one-dimensional swelling pressure tests performed in the CEA (Commisariat à l'Énergie Atomique, France) and CIEMAT (Spain) laboratories. A very satisfactory quantitative description of the experimental observations is obtained that includes a number of complex behaviour features such as size effects and non-monotonic development of swelling pressures. Some microfabric observations using X-ray tomography and mercury intrusion porosimetry lend support to the conceptual approach adopted. The formulation is then applied to the analysis of a long-term large-scale sealing test performed at the Hades underground facility in Belgium, using the same set of hydraulic and mechanical parameters employed in the modelling of the laboratory tests. Although the field observations exhibit a much higher degree of scatter, the basic behaviour of the field sealing test is satisfactorily simulated. A formulation that incorporates basic features of the microfabric of the mixture is thus able to span successfully over a large range of space and time scales. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.sip11.p.015 [article] Hydromechanical behaviour of a heterogeneous compacted soil: experimental observations and modelling [texte imprimé] / A. Gens, Auteur ; B. Vallejan, Auteur ; M. Sanchez, Auteur . - 2011 . - pp. 367–386. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 5 (Mai 2011) . - pp. 367–386 Mots-clés : Laboratory  tests  Fabric/Structure  of  soils  Compaction  Partial  saturation  Expansive  soils  Full-scale  tests Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The paper describes a theoretical and experimental study of the coupled hydromechanical behaviour of a compacted mixture of bentonite powder and bentonite pellets intended as sealing material in underground repositories for nuclear waste. One of the main advantages of the use of powder/pellets mixtures is the reduction of the compaction effort required to achieve the value of average dry density necessary to attain the required swelling potential. However, the heterogeneous fabric of the material requires special approaches in order to describe adequately its behaviour during hydration. A double porosity formulation is presented to account for the presence of two distinct structural levels in the material. Hydraulic equilibrium between the two porosities is not assumed; instead a water exchange term between them is postulated. The formulation is applied to the modelling of a number of one-dimensional swelling pressure tests performed in the CEA (Commisariat à l'Énergie Atomique, France) and CIEMAT (Spain) laboratories. A very satisfactory quantitative description of the experimental observations is obtained that includes a number of complex behaviour features such as size effects and non-monotonic development of swelling pressures. Some microfabric observations using X-ray tomography and mercury intrusion porosimetry lend support to the conceptual approach adopted. The formulation is then applied to the analysis of a long-term large-scale sealing test performed at the Hades underground facility in Belgium, using the same set of hydraulic and mechanical parameters employed in the modelling of the laboratory tests. Although the field observations exhibit a much higher degree of scatter, the basic behaviour of the field sealing test is satisfactorily simulated. A formulation that incorporates basic features of the microfabric of the mixture is thus able to span successfully over a large range of space and time scales. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.sip11.p.015

Soil–environment interactions in geotechnical engineering / A. Gens in Géotechnique, Vol. 60 N° 1 (Janvier 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 1 (Janvier 2010) . - pp. 3–74 Titre : Soil–environment interactions in geotechnical engineering Type de document : texte imprimé Auteurs : A. Gens, Auteur Année de publication : 2011 Article en page(s) : pp. 3–74 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Suction  Snow  Ice  and  frost  Environmental  engineering  Temperature  effects  Constitutive  relations  Partial  saturation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The range of problems that geotechnical engineers must face is increasing in complexity and scope. Often, complexity arises from the interaction between the soil and the environment – the topic of this lecture. To deal with this type of problem, the classical soil mechanics formulation is progressively generalised in order to incorporate the effects of new phenomena and new variables on soil behaviour. Recent advances in unsaturated soil mechanics are presented first: it is shown that they provide a consistent framework for understanding the engineering behaviour of unsaturated soils, and the effects of suction and moisture changes. Building on those developments, soil behaviour is further explored by considering thermal effects for two opposite cases: high temperatures, associated with the problem of storage and disposal of high-level radioactive waste; and low temperatures in problems of freezing ground. Finally, the lecture examines some issues related to chemical effects on soils and rocks, focusing in part on the subject of tunnelling in sulphate-bearing rocks. In each case new environmental variables are identified, enhanced theoretical formulations are established, and new or extended constitutive laws are presented. Particular emphasis is placed on mechanical constitutive equations, as they are especially important in geotechnical engineering. The lecture includes summary accounts of a number of case histories that illustrate the relevance and implications of the developments described for geotechnical engineering practice. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/search?value1='suction'&option1=fulltext [article] Soil–environment interactions in geotechnical engineering [texte imprimé] / A. Gens, Auteur . - 2011 . - pp. 3–74. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 1 (Janvier 2010) . - pp. 3–74 Mots-clés : Suction  Snow  Ice  and  frost  Environmental  engineering  Temperature  effects  Constitutive  relations  Partial  saturation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The range of problems that geotechnical engineers must face is increasing in complexity and scope. Often, complexity arises from the interaction between the soil and the environment – the topic of this lecture. To deal with this type of problem, the classical soil mechanics formulation is progressively generalised in order to incorporate the effects of new phenomena and new variables on soil behaviour. Recent advances in unsaturated soil mechanics are presented first: it is shown that they provide a consistent framework for understanding the engineering behaviour of unsaturated soils, and the effects of suction and moisture changes. Building on those developments, soil behaviour is further explored by considering thermal effects for two opposite cases: high temperatures, associated with the problem of storage and disposal of high-level radioactive waste; and low temperatures in problems of freezing ground. Finally, the lecture examines some issues related to chemical effects on soils and rocks, focusing in part on the subject of tunnelling in sulphate-bearing rocks. In each case new environmental variables are identified, enhanced theoretical formulations are established, and new or extended constitutive laws are presented. Particular emphasis is placed on mechanical constitutive equations, as they are especially important in geotechnical engineering. The lecture includes summary accounts of a number of case histories that illustrate the relevance and implications of the developments described for geotechnical engineering practice. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/search?value1='suction'&option1=fulltext