Effective stress regime around a jacked steel pile during installation ageing and load testing in chalk

Buckley, R. M. , Jardine, R. J., kontoe, S. and Lehane, B. M. (2018) Effective stress regime around a jacked steel pile during installation ageing and load testing in chalk. Canadian Geotechnical Journal, 55(11), pp. 1577-1591. (doi: 10.1139/cgj-2017-0145)

[img] Text
229112.pdf - Accepted Version



This paper reports experiments with 102 mm diameter closed-ended instrumented Imperial College piles (ICPs) jacked into low- to medium-density chalk at a well-characterized UK test site. The “ICP” instruments allowed the effective stress regime surrounding the pile shaft to be tracked during pile installation, equalization periods of up to 2.5 months, and load testing under static tension and one-way axial cyclic loading. Installation resistances are shown to be dominated by the pile tip loads. Low installation shaft stresses and radial effective stresses were measured that correlated with local cone penetration test (CPT) tip resistances. Marked shaft total stress reductions and steep stress gradients are demonstrated in the vicinity of the pile tip. The local interface shaft effective stress paths developed during static and cyclic loading displayed trends that resemble those seen in comparable tests in sands. Shaft failure followed the Coulomb law and constrained interface dilation was apparent as the pile experienced drained loading to failure, although with a lesser degree of radial expansion than with sands. Radial effective stresses were also found to fall with time after installation, leading to reductions in shaft capacity as proven by subsequent static tension testing. The jacked, closed-ended, piles’ ageing trends contrast sharply with those found with open piles driven at the same site, indicating that ageing is affected by pile tip geometry and (or) installation method.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Buckley, Dr Roisin
Authors: Buckley, R. M., Jardine, R. J., kontoe, S., and Lehane, B. M.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Canadian Geotechnical Journal
Publisher:NRC Research Press (Canadian Science Publishing)
ISSN (Online):1208-6010
Published Online:27 September 2018
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in Canadian Geotechnical Journal 55(11):1577-1591
Publisher Policy:Reproduced in accordance with the publisher copyright policy

University Staff: Request a correction | Enlighten Editors: Update this record