Continuous flight augering (CFA), also known as auger cast piling, is a technique used in

construction Construction is a general term meaning the art and science to form Physical object, objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Pr ...

to create a concrete

deep foundation A deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation does to a subsurface layer or a range of depths. A pile or piling is a vertical structural eleme ...

. Continuous flight auger has been used in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

since 1966, but its use is relatively new in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. A continuous flight auger drill is used to excavate a hole and concrete is injected through a hollow shaft under pressure as the auger is extracted. Reinforcement is then inserted after the auger is removed. This creates a continuous pile without ever leaving an open hole. Continuous flight augering can be used to construct a secant piled wall which can be used as a

retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ...

or as

shoring Shoring is the process of temporarily supporting a building, vessel, structure, or trench with shores (props) when in danger of collapse or during repairs or alterations. ''Shoring'' comes from ''shore'', a timber or metal prop. Shoring may be verti ...

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 rebar. The finished result is a continuous wall of reinforced concrete that aids and protects workers during excavation.

References

{{reflist Concrete Drilling technology Deep foundations