Documents disponibles écrits par cet auteur

Embankments over soft clay deposits / Henrique Oliveira Magnani in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 1 (Janvier 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 260-264 Titre : Embankments over soft clay deposits : contribution of basal reinforcement and surface sand layer to stability Type de document : texte imprimé Auteurs : Henrique Oliveira Magnani, Auteur ; Mauricio Ehrlich, Auteur ; Marcio S. S. Almeida, Auteur Article en page(s) : pp. 260-264 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Soft  clay  Surface  sand  layer  Reinforcement  Test  embankments  Monitoring  Stability  analyses Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper evaluates the significance of basal reinforcement and the presence of the surface sand layer in the stability. This evaluation is carried out by means of field measurements and stability analyses of three test embankments on soft clay taken to failure. Two of the test embankments were reinforced and one was unreinforced. Stability analyses were carried out taking into account measured values of reinforcement tension forces during construction. The set of analyses have shown that the top sand layer was more important to the stability of the embankments than the basal reinforcement. The cases studied have also shown that the conventional design practice that assumes for the reinforcement a fixed tension contribution may lead to unrealistic higher factor of safety. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&ONLINE=YES&s [...] [article] Embankments over soft clay deposits : contribution of basal reinforcement and surface sand layer to stability [texte imprimé] / Henrique Oliveira Magnani, Auteur ; Mauricio Ehrlich, Auteur ; Marcio S. S. Almeida, Auteur . - pp. 260-264. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 260-264 Mots-clés : Soft  clay  Surface  sand  layer  Reinforcement  Test  embankments  Monitoring  Stability  analyses Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper evaluates the significance of basal reinforcement and the presence of the surface sand layer in the stability. This evaluation is carried out by means of field measurements and stability analyses of three test embankments on soft clay taken to failure. Two of the test embankments were reinforced and one was unreinforced. Stability analyses were carried out taking into account measured values of reinforcement tension forces during construction. The set of analyses have shown that the top sand layer was more important to the stability of the embankments than the basal reinforcement. The cases studied have also shown that the conventional design practice that assumes for the reinforcement a fixed tension contribution may lead to unrealistic higher factor of safety. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&ONLINE=YES&s [...]

Influence of penetration rate on penetrometer resistance / José R. M. S. Oliveira in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 7 (Juillet 2011) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 7 (Juillet 2011) . - pp. 695-703 Titre : Influence of penetration rate on penetrometer resistance Type de document : texte imprimé Auteurs : José R. M. S. Oliveira, Auteur ; Marcio S. S. Almeida, Auteur ; Helena P. G. Motta, Auteur Année de publication : 2011 Article en page(s) : pp. 695-703 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Penetration  tests  Penetration  rate  Backbone  curve  Centrifuge  tests  Silty  tailings Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Penetration resistance in fine-grained soils varies with the rate of penetration. Considering undrained behavior as a reference, as the rate of penetration is reduced, soil resistance increases because of the effects of partial consolidation and soil strengthening immediately ahead of the probe. Many penetration tests have been performed under different rates of penetration to identify the range of drainage characteristics of the soils used, correlating these conditions with laboratory interpretations and in situ tests. A backbone curve relates the variation of the normalized point resistance with the normalized rate of penetration. This work presents an analytical approach to the backbone curve equation used to fit test data. In addition, this paper presents a set of centrifuge tests with variable penetration rates performed with a soil classified as silty tailings, which has different geotechnical behavior from most of the soils used by previous researchers. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i7/p695_s1?isAuthorized=no [article] Influence of penetration rate on penetrometer resistance [texte imprimé] / José R. M. S. Oliveira, Auteur ; Marcio S. S. Almeida, Auteur ; Helena P. G. Motta, Auteur . - 2011 . - pp. 695-703. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 7 (Juillet 2011) . - pp. 695-703 Mots-clés : Penetration  tests  Penetration  rate  Backbone  curve  Centrifuge  tests  Silty  tailings Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Penetration resistance in fine-grained soils varies with the rate of penetration. Considering undrained behavior as a reference, as the rate of penetration is reduced, soil resistance increases because of the effects of partial consolidation and soil strengthening immediately ahead of the probe. Many penetration tests have been performed under different rates of penetration to identify the range of drainage characteristics of the soils used, correlating these conditions with laboratory interpretations and in situ tests. A backbone curve relates the variation of the normalized point resistance with the normalized rate of penetration. This work presents an analytical approach to the backbone curve equation used to fit test data. In addition, this paper presents a set of centrifuge tests with variable penetration rates performed with a soil classified as silty tailings, which has different geotechnical behavior from most of the soils used by previous researchers. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i7/p695_s1?isAuthorized=no

Physical modeling of lateral clay-pipe interaction / José R. M. S. Oliveira in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 950-956 Titre : Physical modeling of lateral clay-pipe interaction Type de document : texte imprimé Auteurs : José R. M. S. Oliveira, Auteur ; Marcio S. S. Almeida, Auteur ; Maria C. F. Almeida, Auteur Année de publication : 2010 Article en page(s) : pp. 950-956 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Soft  soils  Pipelines  Soil-structure  interaction  Model  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents results from physical model testing of lateral clay-pipe interaction. The main reason for this research was the accident in Rio de Janeiro in January 2000 when more than 1×106 l of crude oil was spilled into Guanabara Bay due to thermal buckling of a pipeline. A set of centrifuge tests was performed for a model pipeline at shallow burial depths in order to assess the lateral resistance of the soft clay from the incident site. In addition, a set of 1-g model tests was also performed to observe the failure mechanism in more detail. These tests permitted the development of an analytical model, based on geotechnical and geometrical parameters, able to evaluate the soil resistance when subjected to lateral pipe movements for shallow burial depths. The centrifuge data are then compared with the proposed analytical model and with literature data, revealing good agreement in both cases. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p950_s1?isAuthorized=no [article] Physical modeling of lateral clay-pipe interaction [texte imprimé] / José R. M. S. Oliveira, Auteur ; Marcio S. S. Almeida, Auteur ; Maria C. F. Almeida, Auteur . - 2010 . - pp. 950-956. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 950-956 Mots-clés : Soft  soils  Pipelines  Soil-structure  interaction  Model  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents results from physical model testing of lateral clay-pipe interaction. The main reason for this research was the accident in Rio de Janeiro in January 2000 when more than 1×106 l of crude oil was spilled into Guanabara Bay due to thermal buckling of a pipeline. A set of centrifuge tests was performed for a model pipeline at shallow burial depths in order to assess the lateral resistance of the soft clay from the incident site. In addition, a set of 1-g model tests was also performed to observe the failure mechanism in more detail. These tests permitted the development of an analytical model, based on geotechnical and geometrical parameters, able to evaluate the soil resistance when subjected to lateral pipe movements for shallow burial depths. The centrifuge data are then compared with the proposed analytical model and with literature data, revealing good agreement in both cases. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p950_s1?isAuthorized=no