Carlos Lam (University of Oxford), Viv Troughton (formerly Balfour Beatty Ground Engineering), Stephan Jefferis (University of Oxford and Environmental Geotechnics), and Tony Suckling (Balfour Beatty Ground Engineering).
This paper was first published in GE’s October 2010 issue.
Synthetic polymer support fluids have been used in the UK for about a decade, although naturally derived polymers such as xanthan gum have been used for much longer. Very little research has been carried out to assess the effects of polymer fluids and especially synthetic polymers on pile performance.
A field trial comprising the construction and testing of three piles has been carried out at Stratford in east London. The objectives of the trial were to compare the effects of polymer and bentonite support fluids on pile performance, to assess the effect of extended bore open time for the polymer piles, and to quantify the effect of support fluid contamination on the hardened properties of concrete.
It was found that the two polymer piles significantly outperformed the bentonite pile under the maximum proof load, and that no adverse effect was caused by the extended soil-fluid exposure time in the polymer-supported bore. The two support fluids were also found to have similar effects on concrete quality.