Polymer fluids are now widely used to support excavations for piles and boreholes and more rarely (in the UK) diaphragm walls. Despite this concerns can still be voiced by those not familiar with their behaviour. Concerns include performance of polymers from different suppliers in different grounds and more generally how to specify and manage polymer support fluids. Those who have mastered their use have found that they can offer substantial benefits over conventional bentonite slurries and yet until very recently there was limited published guidance on their use and there are still significant differences in the approaches across the World. In the interest of sharing experience across the foundation industry, this paper presents a case history of the use of a polymer fluid on a major infrastructure project. This project included the largest polymer supported rotary pile ever constructed in the UK; a pile that required 270 m3 of support fluid. The paper highlights the technical challenges and collective operational experience derived from managing such a complex project and the developments in polymer fluid specification that have flowed from it.
Subjects: Rotary pile, drilled shaft, polymer support fluid, bentonite slurry thermal integrity testing
Author: Yue Ouyang, Project Manager, Stephan Jefferis, Director, Paul Wiltcher, Operations Director and Tony Suckling, Director
Publisher: DFI, EFFC