Documents disponibles écrits par cet auteur

Deformations caused by surface loading and tunnelling / K. M. Lee in Géotechnique, Vol. 39 N°1 (Mars 1989) 

Public ISBD [article]  in Géotechnique > Vol. 39 N°1 (Mars 1989) . - pp. 125–140 Titre : Deformations caused by surface loading and tunnelling : The role of elastic anisotropy Type de document : texte imprimé Auteurs : K. M. Lee, Auteur ; R. K. Rowe, Auteur Année de publication : 2007 Article en page(s) : pp. 125–140 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Centrifuge  modelling  Footings/foundations  Flnite  elements  Settlement  Anisotropy  Tunnels Résumé : Elastoplastic finite element analyses were performed to determine the effects of elastic anisotropy on surface settlements caused by a uniform surface loading and by tunnelling. For typical ranges of elastic cross-anisotropic parameters, the effect of anisotropy on settlement induced by surface loading is modest; however, for the case of tunnelling, the effect of elastic anisotropy, in particular the ratio of the independent shear modulus G vh, to vertical modulus E v, should be considered if reasonable predictions of settlement are to be obtained. The practical implications of these find- ings are shown by considering the centrifugal model tunnel tests conducted at Cambridge University. It is found that the anisotropy has a significant effect on the shape of the settlement trough and that reasonable agreement between observa-tion and theory is obtained for G vh/E v, of between 0·2 and O·25, which is smaller thanthe isotropic value of G vh/E v, = 0·33 (for the undrained condition). The reasons for this are discussed. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.1.125 [article] Deformations caused by surface loading and tunnelling : The role of elastic anisotropy [texte imprimé] / K. M. Lee, Auteur ; R. K. Rowe, Auteur . - 2007 . - pp. 125–140. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 39 N°1 (Mars 1989) . - pp. 125–140 Mots-clés : Centrifuge  modelling  Footings/foundations  Flnite  elements  Settlement  Anisotropy  Tunnels Résumé : Elastoplastic finite element analyses were performed to determine the effects of elastic anisotropy on surface settlements caused by a uniform surface loading and by tunnelling. For typical ranges of elastic cross-anisotropic parameters, the effect of anisotropy on settlement induced by surface loading is modest; however, for the case of tunnelling, the effect of elastic anisotropy, in particular the ratio of the independent shear modulus G vh, to vertical modulus E v, should be considered if reasonable predictions of settlement are to be obtained. The practical implications of these find- ings are shown by considering the centrifugal model tunnel tests conducted at Cambridge University. It is found that the anisotropy has a significant effect on the shape of the settlement trough and that reasonable agreement between observa-tion and theory is obtained for G vh/E v, of between 0·2 and O·25, which is smaller thanthe isotropic value of G vh/E v, = 0·33 (for the undrained condition). The reasons for this are discussed. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.1989.39.1.125

Permeation of BTEX through unaged and aged HDPE geomembranes / M. Z. Islam in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 8 (Août 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 8 (Août 2009) . - pp. 1130–1140 Titre : Permeation of BTEX through unaged and aged HDPE geomembranes Type de document : texte imprimé Auteurs : M. Z. Islam, Auteur ; R. K. Rowe, Auteur Année de publication : 2009 Article en page(s) : pp. 1130–1140 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Geomembranes  Aging  Crystal  growth  Volatile  organic  chemicals  Polyethylene Résumé : The effects of aging of high-density polyethylene (HDPE) geomembranes on the diffusion and partitioning of a group of volatile organic compounds (VOCs) are examined. Two different 1.5mm thick HDPE geomembranes were aged in the laboratory at 85°C by immersing in a synthetic leachate for up to 32months . The results of partitioning and diffusion tests performed at room temperature on both unaged and aged geomembranes using a dilute aqueous solution containing four VOCs commonly found in landfill leachates [benzene, toluene, ethylbenzene, and xylenes (BTEX)] are reported. The diffusion and partitioning coefficients decreased with increased aging. The calculated permeation coefficients decreased by 36–62% after aging the geomembrane for about 10–32months . This decrease in diffusion, partitioning, and permeation coefficients is related to the increase in geomembrane crystallinity during aging. A relationship between partitioning, diffusion, and permeation coefficients with the geomembrane crystallinity is established and could potentially be used to evaluate the migration of VOCs through HDPE geomembranes. Aging of HDPE geomembrane did not increase diffusive transport of organic contaminants. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000056 [article] Permeation of BTEX through unaged and aged HDPE geomembranes [texte imprimé] / M. Z. Islam, Auteur ; R. K. Rowe, Auteur . - 2009 . - pp. 1130–1140. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 8 (Août 2009) . - pp. 1130–1140 Mots-clés : Geomembranes  Aging  Crystal  growth  Volatile  organic  chemicals  Polyethylene Résumé : The effects of aging of high-density polyethylene (HDPE) geomembranes on the diffusion and partitioning of a group of volatile organic compounds (VOCs) are examined. Two different 1.5mm thick HDPE geomembranes were aged in the laboratory at 85°C by immersing in a synthetic leachate for up to 32months . The results of partitioning and diffusion tests performed at room temperature on both unaged and aged geomembranes using a dilute aqueous solution containing four VOCs commonly found in landfill leachates [benzene, toluene, ethylbenzene, and xylenes (BTEX)] are reported. The diffusion and partitioning coefficients decreased with increased aging. The calculated permeation coefficients decreased by 36–62% after aging the geomembrane for about 10–32months . This decrease in diffusion, partitioning, and permeation coefficients is related to the increase in geomembrane crystallinity during aging. A relationship between partitioning, diffusion, and permeation coefficients with the geomembrane crystallinity is established and could potentially be used to evaluate the migration of VOCs through HDPE geomembranes. Aging of HDPE geomembrane did not increase diffusive transport of organic contaminants. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000056