Continuous Flight Auger (CFA)
This technique involves boring with a continuous flight (Hollow Stem) auger which is rotated into the ground until the required depth. Concrete is then pumped into the pile hole through a hollow central stem. The auger supports the sides of the bore as the pile is advanced. As the pile is concreted the auger is retracted, along with the displaced spoil.
This method is very popular in the UK as it can cater for variable ground and water conditions.