The axial behaviour of piles driven in chalk

Jardine, R. J., Buckley, R. M. , Liu, T., Andolffson, T., Byrne, B. W., Kontoe, S., McAdam, R. A., Schranz, F. and Vinck, K. (2023) The axial behaviour of piles driven in chalk. Geotechnique, (doi: 10.1680/jgeot.22.00041) (Early Online Publication)

Abstract

This paper describes research into the poorly understood axial behaviour of piles driven in chalk. Comprehensive dynamic and monotonic axial testing on 27, mostly instrumented, piles undertaken for the ALPACA Joint Industry Projects is reported and interpreted covering: diameters between 139mm and 1.8m; lengths from 3 to 18m; different pile material types; tip and groundwater conditions, and ages after driving. The experiments show the factors that influence resistance most strongly are: (i) pile end-conditions, (ii) slenderness ratio and flexibility, (iii) shaft material, (iv) age after driving, (vi) relative water table depth, and (vii) whether loading is compressive or tensile. Varying the factors systematically identified a remarkable average long-term shaft resistance range from below 11 kPa to more than 200 kPa for piles driven at the same low-to-medium density chalk test site in Kent (UK). Dynamic and static analyses demonstrate that soil resistances to driving (SRD) were generally well-predicted by the Chalk ICP-18 short-term formulation. Considering the piles’ long-term behaviour, the Chalk ICP-18 approach over-predicted capacity, while the widely used CIRIA approach proved over-conservative for most cases. The research enabled the development of a revised ‘ALPACA-SNW’ long-term capacity assessment method that matches the test outcomes far more faithfully.

• Item Type: Articles
• Additional Information: The Authors gratefully acknowledge support from Engineering and Physical Science Research Council (EPSRC) grant EP/P033091/1, Royal Society Newton Advanced Fellowship NA160438 and Supergen ORE Hub 2018 (EPSRC EP/S000747/1). Byrne is supported by the Royal Academy of Engineering under the Research Chairs and Senior Research Fellowships scheme, while Vinck was supported by EPSRC Grant EP/L016826/1, DEME and Imperial College.
• Status: Early Online Publication
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Buckley, Dr Roisin
• Authors: Jardine, R. J., Buckley, R. M., Liu, T., Andolffson, T., Byrne, B. W., Kontoe, S., McAdam, R. A., Schranz, F., and Vinck, K.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Geotechnique
• Publisher: ICE Publishing
• ISSN: 0016-8505
• ISSN (Online): 1751-7656
• Published Online: 13 March 2023
• Copyright Holders: Copyright © 2023 ICE Publishing
• First Published: First published in Geotechnique 2023
• Publisher Policy: Reproduced under a Creative Commons License