Documents disponibles écrits par cet auteur

Physical modelling of deformations around piling augers in clay / C. C. Hird in Géotechnique, Vol. 61 N° 11 (Novembre 2010) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 11 (Novembre 2010) . - pp. 993-999 Titre : Physical modelling of deformations around piling augers in clay Type de document : texte imprimé Auteurs : C. C. Hird, Auteur ; Q. Ni, Auteur ; Guymer, I., Auteur Année de publication : 2011 Article en page(s) : pp. 993-999 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Model  tests  Deformation  Piles  Clays Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Small-scale model tests are reported in which miniature augers were installed in beds of transparent synthetic soil simulating clay. As the auger advanced, the movement of reflective particles seeded into the soil and illuminated by laser light was recorded photographically. The displacement field in a vertical plane aligned with the auger axis was then determined using particle image velocimetry. The pattern of deformation of the soil around an auger of the type used to form a cast-in-situ screw pile was similar to that around a cylindrical straight-sided pushed pile. Deformations around an auger of the type used to form a rotary displacement pile depended on the rotation speed of the auger and the extent to which the flights carried soil upwards away from the tip. Lateral displacements in the model tests exhibited roughly similar trends to those observed in the field. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.t.028 [article] Physical modelling of deformations around piling augers in clay [texte imprimé] / C. C. Hird, Auteur ; Q. Ni, Auteur ; Guymer, I., Auteur . - 2011 . - pp. 993-999. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 11 (Novembre 2010) . - pp. 993-999 Mots-clés : Model  tests  Deformation  Piles  Clays Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Small-scale model tests are reported in which miniature augers were installed in beds of transparent synthetic soil simulating clay. As the auger advanced, the movement of reflective particles seeded into the soil and illuminated by laser light was recorded photographically. The displacement field in a vertical plane aligned with the auger axis was then determined using particle image velocimetry. The pattern of deformation of the soil around an auger of the type used to form a cast-in-situ screw pile was similar to that around a cylindrical straight-sided pushed pile. Deformations around an auger of the type used to form a rotary displacement pile depended on the rotation speed of the auger and the extent to which the flights carried soil upwards away from the tip. Lateral displacements in the model tests exhibited roughly similar trends to those observed in the field. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.t.028

Physical modelling of pile penetration in clay using transparent soil and particle image velocimetry / Q. Ni in Géotechnique, Vol. 60 N° 2 (Fevrier 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 2 (Fevrier 2010) . - pp. 121–132 Titre : Physical modelling of pile penetration in clay using transparent soil and particle image velocimetry Type de document : texte imprimé Auteurs : Q. Ni, Auteur ; C. C. Hird, Auteur ; Guymer, I., Auteur Année de publication : 2011 Article en page(s) : pp. 121–132 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Clays  Model  tests  Deformation  Piles Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A small-scale physical modelling method was developed to study the movement of clay during pile installation. The clay was simulated using a mixture of amorphous silica and mineral oil, which becomes almost transparent when the refractive indices of the oil and the silica are well matched. After adding reflective particles and consolidating the mixture in a transparent container, cylindrical model piles were driven vertically at the centre. A vertical section aligned with the pile centreline was illuminated by a laser light sheet, and a sequence of digital images was recorded. These were analysed using particle image velocimetry, and the complete displacement distribution during the pile installation was obtained. Notwithstanding some discrepancies at shallow depths, the observed displacements generally showed fairly good agreement with the theoretical predictions of the shallow strain path method (SSPM) once the effect of some soil trapped beneath the flat pile tip was taken into account. Normalisation of the horizontal and vertical components of movement employing both the pile length and radius, based on SSPM theory, was shown to be valid. The normalised vertical displacement contours were similar to those published by previous researchers. The results of this study could be used to assess the impact of disturbance due to pile installation on, for example, buried services or archaeology. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.052 [article] Physical modelling of pile penetration in clay using transparent soil and particle image velocimetry [texte imprimé] / Q. Ni, Auteur ; C. C. Hird, Auteur ; Guymer, I., Auteur . - 2011 . - pp. 121–132. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 2 (Fevrier 2010) . - pp. 121–132 Mots-clés : Clays  Model  tests  Deformation  Piles Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A small-scale physical modelling method was developed to study the movement of clay during pile installation. The clay was simulated using a mixture of amorphous silica and mineral oil, which becomes almost transparent when the refractive indices of the oil and the silica are well matched. After adding reflective particles and consolidating the mixture in a transparent container, cylindrical model piles were driven vertically at the centre. A vertical section aligned with the pile centreline was illuminated by a laser light sheet, and a sequence of digital images was recorded. These were analysed using particle image velocimetry, and the complete displacement distribution during the pile installation was obtained. Notwithstanding some discrepancies at shallow depths, the observed displacements generally showed fairly good agreement with the theoretical predictions of the shallow strain path method (SSPM) once the effect of some soil trapped beneath the flat pile tip was taken into account. Normalisation of the horizontal and vertical components of movement employing both the pile length and radius, based on SSPM theory, was shown to be valid. The normalised vertical displacement contours were similar to those published by previous researchers. The results of this study could be used to assess the impact of disturbance due to pile installation on, for example, buried services or archaeology. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.8.p.052