Displacement piling methods, such as driven precast or vibroconcrete columns, are often specified in preference to continuos flight augers for contaminated ground. This is because CFA can cause contaminant migration and spoil disposal problems. But apart from being noisy, displacement methods are not always ideal. Vibro piling does not work in all types of ground. And the use of smooth sided driven piles in contaminated ground raises fears of creating vertical contaminant pathways along the side of the pile.
Now piling specialist Pennine has developed the Penpile, a CFA system which is more suited to use in contaminated ground. The design of the new auger produces lateral displacement of soil, meaning very little spoil is created. In granular soils the Penpile can be used with high pressure concrete to create an enlarged pile base, which can significantly increase bearing capacity. The Penpile system has the advantage of being relatively quiet and is suited to urban locations.