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Dilatancy of the interface between a structure and gravelly soil / G. Zhang in Géotechnique, Vol. LXI N° 1 (Janvier 2011) 

Public ISBD [article]  in Géotechnique > Vol. LXI N° 1 (Janvier 2011) . - pp. 75–84 Titre : Dilatancy of the interface between a structure and gravelly soil Type de document : texte imprimé Auteurs : G. Zhang, Auteur ; L. Wang, Auteur ; J.-M. Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 75–84 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Gravels  Soil/structure  interaction  Constitutive  relations  Laboratory  tests  Shear  strength Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Dilatancy is one of the key properties of the soil–structure interface. A number of monotonic and cyclic shear tests were analysed to derive the rules and the dilatancy mechanism of the interface between a structure and a gravelly soil; diverse influential factors were considered, such as soil type, roughness of the structure and normal stress. The volumetric change due to the dilatancy consists of a reversible and irreversible dilatancy component, each of which has different mechanisms, different rules and different control factors. The reversible dilatancy component is strongly dependent on the direction of the applied shear after an initial application of shear loading. The irreversible dilatancy component gradually increases owing to the continued application of shear and exhibits a close relationship with the evolution of the physical state. The volumetric change that is due to the dilatancy mainly depends on part of the tangential displacement which corresponds to the deformation of the soil that is constrained by the structure; such a part of the tangential displacement is significantly dependent on the state of the entire tangential displacement, on the normal stress and on the features of both the structure and the soil. The roughness of the structure, the behaviour of the soil and the normal stress have significant effects on the dilatancy behaviour of the interface. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.051 [article] Dilatancy of the interface between a structure and gravelly soil [texte imprimé] / G. Zhang, Auteur ; L. Wang, Auteur ; J.-M. Zhang, Auteur . - 2011 . - pp. 75–84. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. LXI N° 1 (Janvier 2011) . - pp. 75–84 Mots-clés : Gravels  Soil/structure  interaction  Constitutive  relations  Laboratory  tests  Shear  strength Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Dilatancy is one of the key properties of the soil–structure interface. A number of monotonic and cyclic shear tests were analysed to derive the rules and the dilatancy mechanism of the interface between a structure and a gravelly soil; diverse influential factors were considered, such as soil type, roughness of the structure and normal stress. The volumetric change due to the dilatancy consists of a reversible and irreversible dilatancy component, each of which has different mechanisms, different rules and different control factors. The reversible dilatancy component is strongly dependent on the direction of the applied shear after an initial application of shear loading. The irreversible dilatancy component gradually increases owing to the continued application of shear and exhibits a close relationship with the evolution of the physical state. The volumetric change that is due to the dilatancy mainly depends on part of the tangential displacement which corresponds to the deformation of the soil that is constrained by the structure; such a part of the tangential displacement is significantly dependent on the state of the entire tangential displacement, on the normal stress and on the features of both the structure and the soil. The roughness of the structure, the behaviour of the soil and the normal stress have significant effects on the dilatancy behaviour of the interface. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.051

The corrosion behavior of carbon steel in CO2-saturated NaCl crevice solution containing acetic acid / Q. Hu in Materials and corrosion, Vol. 63 N° 8 (Août 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 8 (Août 2012) . - pp. 720–728 Titre : The corrosion behavior of carbon steel in CO2-saturated NaCl crevice solution containing acetic acid Type de document : texte imprimé Auteurs : Q. Hu, Auteur ; X. Guo, Auteur ; G. Zhang, Auteur Année de publication : 2013 Article en page(s) : pp. 720–728 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Carbon  steel;  crevice  corrosion;  electrochemical  noise;  electrochemical  impedance  spectroscopy Résumé : The corrosion behavior of X52 carbon steel electrodes in CO2-saturated NaCl crevice solution containing HAc was investigated by electrochemical measurements. Chemical environment measurements by Cl− and pH microprobes show an enrichment of Cl− ions and an increase of pH values inside the crevice. Moreover, both increments could accelerate with the decreasing dimension of the crevice mouth due to the high diffusive resistance. When the electrode in the crevice solution is coupled with the electrode in bulk solution, the alkalization and the enrichment of Cl− ions in the crevice solution can result in a negative shift of potential of the electrode in crevice solution, while the potential of the electrode in bulk solution shifts positively during the corrosion process. Thus, a galvanic corrosion is established with the electrode in the crevice solution acting as anode while another in the bulk solution as cathode, i.e., the corrosion in the crevice solution was enhanced while the corrosion in the bulk solution was retarded. The anodic dissolution and the cathodic reduction processes dominate in the crevice solution and in the bulk solution, respectively. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006027/abstract [article] The corrosion behavior of carbon steel in CO2-saturated NaCl crevice solution containing acetic acid [texte imprimé] / Q. Hu, Auteur ; X. Guo, Auteur ; G. Zhang, Auteur . - 2013 . - pp. 720–728. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 8 (Août 2012) . - pp. 720–728 Mots-clés : Carbon  steel;  crevice  corrosion;  electrochemical  noise;  electrochemical  impedance  spectroscopy Résumé : The corrosion behavior of X52 carbon steel electrodes in CO2-saturated NaCl crevice solution containing HAc was investigated by electrochemical measurements. Chemical environment measurements by Cl− and pH microprobes show an enrichment of Cl− ions and an increase of pH values inside the crevice. Moreover, both increments could accelerate with the decreasing dimension of the crevice mouth due to the high diffusive resistance. When the electrode in the crevice solution is coupled with the electrode in bulk solution, the alkalization and the enrichment of Cl− ions in the crevice solution can result in a negative shift of potential of the electrode in crevice solution, while the potential of the electrode in bulk solution shifts positively during the corrosion process. Thus, a galvanic corrosion is established with the electrode in the crevice solution acting as anode while another in the bulk solution as cathode, i.e., the corrosion in the crevice solution was enhanced while the corrosion in the bulk solution was retarded. The anodic dissolution and the cathodic reduction processes dominate in the crevice solution and in the bulk solution, respectively. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006027/abstract