Contact Pressure and Stress Distribution in Piled Raft Foundation Subjected to Vertical Loading

Ahmed Alnuaim, Hany El Naggar, Hesham El Naggar

In the proceedings of: GeoMontréal 2013: 66th Canadian Geotechnical Conference; 11th joint with IAH-CNC

Session: Foundations V

ABSTRACT: The use of piled raft foundation has been adopted in large number of mega projects recently. Therefore, a noticeable attention has been drawn toward better understanding of the performance of piled raft foundation subjected to vertical loading. Piled raft foundations have a complex soil-structure interaction scheme including the pile-soil interaction, pile-pile interaction, raft-soil interaction, and finally the pile-raft interaction. In this paper, a 3D finite element model was developed and verified using a geotechnical centrifuge test data which was capable to simulate the behavior and stress distribution of piled-raft centrifuge model accurately. This calibrated model was used to investigate the effect of number of parameters, such as raft thickness, piles spacing and pile diameter, on the contact pressure between the raft and the soil; and the stress distribution in the raft. In addition, the stress concentration at the point between piles and raft was examined under the same parameters which may experience relatively high tension stress especially for thin raft.

RÉSUMÉ: Les utilisations du radier sur des pieux a été adopté récemment en grand nombre de mégaprojets. Par conséquent, une attention notable a été attirée vers une meilleure compréhension de la performance du radier sur des pieux soumis à une charge verticale. Les radiers sur des pieux ont un schéma complexe d'interaction sol-structure comprenant de l'interaction sol-pieu, l'interaction pieu-pieu, l'interaction radier-sol, et finalement l'interaction pieu-radier. Dans cet article, un modèle des éléments finis 3D a été développé et vérifié en utilisant les données essai centrifugeuse et il était capable de simuler précisément le comportement et la distribution sur des pieux. Ce modèle calibré a été utilisé pour étudier l'effet du nombre de paramètres tels que l'épaisseur du radier, r la pression de contact entre le radier et le sol ; et la distribution des contraintes dans le radier. De plus, la concentration de contraintes au niveau de la connexion entre les pieux et le radier sera examinée selon les mêmes paramètres qui peuvent subir une contrainte de tension relativement haute spécialement pour un radier mince.

Access this article:
Canadian Geotechnical Society members can access to this article, along with all other Canadian Geotechnical Conference proceedings, in the Member Area. Conference proceedings are also available in many libraries.

Cite this article:
Ahmed Alnuaim; Hany El Naggar; Hesham El Naggar (2013) Contact Pressure and Stress Distribution in Piled Raft Foundation Subjected to Vertical Loading in GEO2013. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoMon2013Paper173,author = Ahmed Alnuaim; Hany El Naggar; Hesham El Naggar,title = Contact Pressure and Stress Distribution in Piled Raft Foundation Subjected to Vertical Loading ,year = 2013}