Continuous flight augering (CFA) is a technique used in construction to create concrete piles.
Continuous flight auger has been used in the United Kingdom since 1966[1], but its use is relatively new in the United States. A continuous flight augering drill is used to excavate a hole and concrete is injected through a hollow shaft under pressure as the auger is extracted. This creates a continuous pile without ever leaving an open hole.
Continuous flight augering can be used to construct a secant pile wall which can be used as a retaining wall or as shoring during excavation. Once initial piles are set with concrete, other shafts are augured between them, slicing into the original piles, with the new ones receiving reinforcement. The finished result is a continuous wall of reinforced concrete that aids and protects workers during excavation.[2]