Imperial College London
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ProfessorRichardJardine

Faculty of Engineering, Department of Civil and Environmental Engineering

Proconsul and Professor of Geomechanics
 
 
 
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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}
}
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RIS format (EndNote, RefMan)

TY  - CPAPER
AB  - 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  -
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