Performance of polymer support fluids for piling and diaphragm walls

Polymer support fluids are emerging in the industry for piling work, but have yet to be used for diaphragm walls in the UK, though they are reported to be widely used in the USA. Pile tests with properly managed polymer fluids have shown that they can result in better shaft friction than bentonite slurries. Furthermore, polymer fluids have a simpler site footprint than their bentonite slurry counterparts, especially as complex and costly soil-slurry separation plants are not required for polymer fluids. Current guidelines provide limited recommendations on polymer fluid use due to a lack of test data and understanding.

At present, there has not been extensive research into the mechanism through which these polymer fluids act. Over the course of the studentship, research in to both the theoretical and the more practical side of polymer support fluids will be conducted, developing a fuller understanding of the behaviour of polymer fluids and then focusing on the optimisation of site practices, including maintenance of slurry properties while in use and, in site control procedures. Having a clear understanding of the mechanism through which the polymer support fluids act, will be integral in developing on site methods through which the condition of the polymers can be determined quickly and simply. The development of such methods is one of the most crucial outcomes of the studentship, as it will enable contractors to test the polymers while at the construction site thus allowing them to determine the condition of the polymer, and to ensure that the polymer support fluids being used have not been degraded either during the mixing stage or during cleaning of the polymer fluid.