Continuous Flight Auger (CFA) piles are formed by drilling a continuous flight auger into the ground. The sides of the hole are supported at all times by the soil-filled auger, eliminating the need for any temporary casings. Once the required depth is reached, a specialised CFA mix is pumped down the stem as the auger is slowly withdrawn from the ground. There is a reduced risk of damage to nearby buildings as there is no vibration and noise levels are limited.
Whilst the CFA pile is an excellent option for working in cities and vibration sensitive areas, there are certain limitations to this type of pile:
- It is a friction pile and very dependent on the types of soil formations
- There is more wastage compared to the driven piles as the piles have to be cast to ground level
- The process generates spoil
Fairbrother Geotechnical Engineering offers CFA piles with diameters of 400mm, 500m and 600mm with working loads from 500kN to 1600kN.