Documents disponibles écrits par cet auteur

Effects of bond crushing on the settlements of shallow foundations on soft rocks / R. Nova in Géotechnique, Vol. 61 N° 3 (Mars 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 3 (Mars 2011) . - pp. 247–261 Titre : Effects of bond crushing on the settlements of shallow foundations on soft rocks Type de document : texte imprimé Auteurs : R. Nova, Auteur ; M. Parma, Auteur Année de publication : 2011 Article en page(s) : pp. 247–261 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Plasticity  Settlement  Model  tests  Particle  crushing/crushability  Footings/Foundations  Soft  rocks Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The paper presents a model capable of describing the behaviour of shallow foundations on soft rocks when subjected to eccentric loading. The model is based on the concept of a ‘macroelement'. According to this concept, the foundation and the subsoil can be seen as a unique volume element. A mathematical relationship is established that links the force and moment acting on the foundation and the corresponding displacement and rotation, as if they were generalised stresses and strains, respectively. This relationship is based on the theory of hardening plasticity, with two hardening variables, both functions of the permanent generalised strains. It is assumed that the second of such variables, connected to the action of intergranular bonds, monotonically decreases as strains progress and bonds crush. It is shown that the model can reproduce quite well the observed displacement and rotation of a model circular foundation on a layer of calcarenite. A parametric study also highlights that the model can in principle predict the phenomenon of collapse, actually experienced by foundations on high-porosity rocks when a certain generalised stress or strain threshold is reached. It is suggested that such a phenomenon can take place when bonds are characterised by high strength that is rapidly decreasing with strain. It is finally shown that weathering-induced collapse under constant external loading can also, in principle, be modelled in this framework. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.7.00183 [article] Effects of bond crushing on the settlements of shallow foundations on soft rocks [texte imprimé] / R. Nova, Auteur ; M. Parma, Auteur . - 2011 . - pp. 247–261. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 3 (Mars 2011) . - pp. 247–261 Mots-clés : Plasticity  Settlement  Model  tests  Particle  crushing/crushability  Footings/Foundations  Soft  rocks Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The paper presents a model capable of describing the behaviour of shallow foundations on soft rocks when subjected to eccentric loading. The model is based on the concept of a ‘macroelement'. According to this concept, the foundation and the subsoil can be seen as a unique volume element. A mathematical relationship is established that links the force and moment acting on the foundation and the corresponding displacement and rotation, as if they were generalised stresses and strains, respectively. This relationship is based on the theory of hardening plasticity, with two hardening variables, both functions of the permanent generalised strains. It is assumed that the second of such variables, connected to the action of intergranular bonds, monotonically decreases as strains progress and bonds crush. It is shown that the model can reproduce quite well the observed displacement and rotation of a model circular foundation on a layer of calcarenite. A parametric study also highlights that the model can in principle predict the phenomenon of collapse, actually experienced by foundations on high-porosity rocks when a certain generalised stress or strain threshold is reached. It is suggested that such a phenomenon can take place when bonds are characterised by high strength that is rapidly decreasing with strain. It is finally shown that weathering-induced collapse under constant external loading can also, in principle, be modelled in this framework. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.7.00183

Yield design of reinforced earth walls by a homogenization method / P. De Buhan in Géotechnique, Vol. 39 N°2 (Juin 1989) 

Public ISBD [article]  in Géotechnique > Vol. 39 N°2 (Juin 1989) . - pp. 189 –201 Titre : Yield design of reinforced earth walls by a homogenization method Type de document : texte imprimé Auteurs : P. De Buhan, Auteur ; R. Mangiavacchi, Auteur ; R. Nova, Auteur Année de publication : 2007 Article en page(s) : pp. 189 –201 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Stability  Failure  Limit  state  design  Reinforced  earth  Retaining  walls  Anisotropy Résumé : The increasing use of the reinforced earth technique in geotechnical engineering requires the development of reliable and practical yield design methods for reinforced earthworks. The method presented in this Paper originates from the idea that, from a macroscopic point of view, reinforced earth can be regarded as a homogeneous material with anisotropic properties, owing to the existence of privileged orientations due to the reinforcing strips. The strength criterion of such an equivalent material, which can be determined theoretically starting from the strength data of the reinforced earth components, turns out to be of the anisotropic frictional type. This criterion is applied to the stability analysis of a reinforced earth wall, making use of the yield design kinematic approach with rigid block failure mechanisms. The theoretical estimates obtained for the collapse height of the wall through this method appear to be in better agreement with experimental results than the values derived from classical design methods. Despite some limitations outlined in the Paper, the proposed yield design homogenization procedure may become an appropriate design method for reinforced soil structures in general. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.2.189 [article] Yield design of reinforced earth walls by a homogenization method [texte imprimé] / P. De Buhan, Auteur ; R. Mangiavacchi, Auteur ; R. Nova, Auteur . - 2007 . - pp. 189 –201. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 39 N°2 (Juin 1989) . - pp. 189 –201 Mots-clés : Stability  Failure  Limit  state  design  Reinforced  earth  Retaining  walls  Anisotropy Résumé : The increasing use of the reinforced earth technique in geotechnical engineering requires the development of reliable and practical yield design methods for reinforced earthworks. The method presented in this Paper originates from the idea that, from a macroscopic point of view, reinforced earth can be regarded as a homogeneous material with anisotropic properties, owing to the existence of privileged orientations due to the reinforcing strips. The strength criterion of such an equivalent material, which can be determined theoretically starting from the strength data of the reinforced earth components, turns out to be of the anisotropic frictional type. This criterion is applied to the stability analysis of a reinforced earth wall, making use of the yield design kinematic approach with rigid block failure mechanisms. The theoretical estimates obtained for the collapse height of the wall through this method appear to be in better agreement with experimental results than the values derived from classical design methods. Despite some limitations outlined in the Paper, the proposed yield design homogenization procedure may become an appropriate design method for reinforced soil structures in general. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.2.189