Imperial College London

ProfessorRichardJardine

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Consul for the Faculty of Engineering & the Business School
 
 
 
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Contact

 

+44 (0)20 7594 6083r.jardine CV

 
 
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Assistant

 

Ms Sue Feller +44 (0)20 7594 6077

 
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Location

 

532Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@inproceedings{Doughty:2018:10.1680/eiccf.64072.695,
author = {Doughty, LJ and Buckley, RM and Jardine, RJ},
doi = {10.1680/eiccf.64072.695},
pages = {695--701},
title = {Investigating the effect of ageing on the behaviour of chalk putty},
url = {http://dx.doi.org/10.1680/eiccf.64072.695},
year = {2018}
}

RIS format (EndNote, RefMan)

TY  - CPAPER
AB - © 2018 Engineering in Chalk - Proceedings of the Chalk 2018 Conference. All rights reserved. Substantial recent investment in offshore wind energy developments and other foundation projects in chalk dominated locations has created an urgent need for a better understanding of how driven piles behave in this variable and unpredictable material. Pile driving in chalk is known to create a remoulded zone of chalk 'putty' around the pile which mobilises low shaft resistance on installation; however, shaft capacity has been reported to increase over time through a process referred to as pile 'set-up' or ageing. Although field evidence of ageing has been reported, the potential role of the chalk putty's behaviour in the ageing process is not well understood. This is partly due to a lack of published laboratory testing on chalk samples which have been conditioned to represent the conditions adjacent to a pile after driving. This paper presents selected results from a suite of laboratory tests undertaken at Imperial College London. Specimens from intact Maas-trichtian Chalk were reduced to putty by Proctor compaction applied at natural water content and subjected to either drained or undrained ageing for periods of between 0 and 28 days. Consolidated undrained triaxial tests, with pore water pressure measurement and local strain measurements, were undertaken on the aged specimens, along with thixotropy testing on unconsolidated samples employing a fall cone. An interpretation of the test results within a critical state framework combined with a conceptual small strain stiffness model is presented. The ageing of chalk putty is shown to encompass a combination of consolidation, thixotropic hardening and re-cementation, with small increases in undrained shear strength seen due to thixotropic hardening, and larger increases in strength evident following consolidation.
AU - Doughty,LJ
AU - Buckley,RM
AU - Jardine,RJ
DO - 10.1680/eiccf.64072.695
EP - 701
PY - 2018///
SP - 695
TI - Investigating the effect of ageing on the behaviour of chalk putty
UR - http://dx.doi.org/10.1680/eiccf.64072.695
ER -