Introducing the zero-trim pile technique: a more sustainable alternative to pile cropping

Standard practice for bored concrete pile construction is to over-pour the concrete and crop the piles down after curing to ensure they are sound at cut-off level. This paper introduces an innovative ‘zero-trim pile’ technique, which has been trialled on the UK’s High Speed Two railway project. It eliminates the need for cropping by sucking out wet concrete above cut-off level. This increases safety, reduces noise, saves time, improves accuracy and avoids cracking. This paper reviews lessons learned from the trials and outlines steps for successful implementation of the technique on a wide range of in situ concrete piling and diaphragm walling projects.