Documents disponibles écrits par cet auteur

Modeling triaxial test on intact rock using discrete element method with membrane boundary / Wang, Yuannian in Journal of engineering mechanics, Vol. 135 N° 9 (Septembre 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 9 (Septembre 2009) . - pp. 1029-1037 Titre : Modeling triaxial test on intact rock using discrete element method with membrane boundary Type de document : texte imprimé Auteurs : Wang, Yuannian, Auteur ; Tonon, Fulvio, Auteur Article en page(s) : pp. 1029-1037 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Membranes  Discrete  elements  Boundaries  Triaxial  tests  Rocks. Résumé : A new membrane boundary that applies realistic fluid confining pressure has been developed for modeling triaxial tests on intact rock by using the discrete element method. To realistically simulate the confining pressure, the new approach applies updated boundary force rather than a “wall” boundary. The applied forces only act on the boundary particles, which are identified and updated periodically. Comparisons between rigid-wall boundary and membrane boundary show that rigid-wall boundary can significantly alter the material response especially the material strength. The effect of confining pressures on the simulated results of triaxial tests is also investigated. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...] [article] Modeling triaxial test on intact rock using discrete element method with membrane boundary [texte imprimé] / Wang, Yuannian, Auteur ; Tonon, Fulvio, Auteur . - pp. 1029-1037. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 9 (Septembre 2009) . - pp. 1029-1037 Mots-clés : Membranes  Discrete  elements  Boundaries  Triaxial  tests  Rocks. Résumé : A new membrane boundary that applies realistic fluid confining pressure has been developed for modeling triaxial tests on intact rock by using the discrete element method. To realistically simulate the confining pressure, the new approach applies updated boundary force rather than a “wall” boundary. The applied forces only act on the boundary particles, which are identified and updated periodically. Comparisons between rigid-wall boundary and membrane boundary show that rigid-wall boundary can significantly alter the material response especially the material strength. The effect of confining pressures on the simulated results of triaxial tests is also investigated. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...]

Numerical study of the effect of verification core hole on the point bearing capacity of drilled shafts / Heejung Youn in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1287-1297 Titre : Numerical study of the effect of verification core hole on the point bearing capacity of drilled shafts Type de document : texte imprimé Auteurs : Heejung Youn, Auteur ; Tonon, Fulvio, Auteur Année de publication : 2010 Article en page(s) : pp. 1287-1297 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Verification  core  hole  Drying-duration  Numerical  analysis  Drilled  shafts  Clay  shales  Point  bearing  capacity  Degradation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a numerical investigation of the effect of a verification core hole on the point bearing capacity of drilled shafts installed in clay shales. The verification core extracted at the shaft tip may reduce the point bearing capacity of drilled shafts as a result of degradation of clay shales and imperfect core hole infill. Finite-element analyses were conducted using the Mohr-Coulomb model with total stress material parameters estimated from laboratory tests. A series of load-displacement curves was calculated for 1 cycle of air drying and wetting; different drying durations and different core hole conditions were considered; and the point bearing capacity was determined at 3 and 5% shaft diameter displacements. The numerical analyses indicate that the point bearing capacity of drilled shafts with a verification core hole does not decrease for most cases, and the maximum reduction merely reaches 5%. Recommendations are made to reduce the effect of the verification core extracted at the shaft bottom during construction. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1287_s1?isAuthorized=no [article] Numerical study of the effect of verification core hole on the point bearing capacity of drilled shafts [texte imprimé] / Heejung Youn, Auteur ; Tonon, Fulvio, Auteur . - 2010 . - pp. 1287-1297. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1287-1297 Mots-clés : Verification  core  hole  Drying-duration  Numerical  analysis  Drilled  shafts  Clay  shales  Point  bearing  capacity  Degradation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a numerical investigation of the effect of a verification core hole on the point bearing capacity of drilled shafts installed in clay shales. The verification core extracted at the shaft tip may reduce the point bearing capacity of drilled shafts as a result of degradation of clay shales and imperfect core hole infill. Finite-element analyses were conducted using the Mohr-Coulomb model with total stress material parameters estimated from laboratory tests. A series of load-displacement curves was calculated for 1 cycle of air drying and wetting; different drying durations and different core hole conditions were considered; and the point bearing capacity was determined at 3 and 5% shaft diameter displacements. The numerical analyses indicate that the point bearing capacity of drilled shafts with a verification core hole does not decrease for most cases, and the maximum reduction merely reaches 5%. Recommendations are made to reduce the effect of the verification core extracted at the shaft bottom during construction. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1287_s1?isAuthorized=no

Prediction of rock block stability and scour depth in plunge pools / Pooyan Asadollahi in Journal of hydraulic research, Vol. 49 N° 6 (Novembre/Décembre 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 6 (Novembre/Décembre 2011) . - pp. 750-756 Titre : Prediction of rock block stability and scour depth in plunge pools Type de document : texte imprimé Auteurs : Pooyan Asadollahi, Auteur ; Tonon, Fulvio, Auteur ; Matteo P.E.A. Federspiel, Auteur Année de publication : 2012 Article en page(s) : pp. 750-756 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Dam  safety  Fracture  Rock  Scour  Spillway Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Block Stability in 3 Dimensions (BS3D) is an incremental-iterative algorithm and code to analyse general failure modes of rock blocks subjected to generic forces, including non-conservative forces such as water pressure. This algorithm is used to investigate the effect of high-velocity water jet impact on the stability of single rock blocks in plunge pools. After reviewing the literature, an approach is proposed to estimate the dynamic water pressure fluctuations at the pool bottom and in rock fractures. The approach is validated using an experimental study. In addition, by comparing the results of these analyses to additional experimental results, a scour threshold is introduced for plunge pools. It is found that if the maximum upward block displacement is larger than a quarter of the block height, the block is most probably removed from its mould. The proposed approach and threshold are validated using case histories that indicate excellent match between prediction and observed scour depth. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.618055 [article] Prediction of rock block stability and scour depth in plunge pools [texte imprimé] / Pooyan Asadollahi, Auteur ; Tonon, Fulvio, Auteur ; Matteo P.E.A. Federspiel, Auteur . - 2012 . - pp. 750-756. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 6 (Novembre/Décembre 2011) . - pp. 750-756 Mots-clés : Dam  safety  Fracture  Rock  Scour  Spillway Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Block Stability in 3 Dimensions (BS3D) is an incremental-iterative algorithm and code to analyse general failure modes of rock blocks subjected to generic forces, including non-conservative forces such as water pressure. This algorithm is used to investigate the effect of high-velocity water jet impact on the stability of single rock blocks in plunge pools. After reviewing the literature, an approach is proposed to estimate the dynamic water pressure fluctuations at the pool bottom and in rock fractures. The approach is validated using an experimental study. In addition, by comparing the results of these analyses to additional experimental results, a scour threshold is introduced for plunge pools. It is found that if the maximum upward block displacement is larger than a quarter of the block height, the block is most probably removed from its mould. The proposed approach and threshold are validated using case histories that indicate excellent match between prediction and observed scour depth. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.618055