Continuous flight auger pile (CFA)

1. Positioning of the CFA rig over proposed pile position.

2. Commence augering into ground to design depth. The continuous flight auger and soil held within the flights support the sides of the pile bore during this phase. An expendable cap or flap on the bottom of the lead-flight prevent soil from entering the hollow stem of the auger.

3. Design depth reached.

4. Concrete is pumped to the base of the pile bore through the CFA system and through the hollow stem of the flights. As the auger is extracted, the pumped concrete maintains stability of the pile bore. No voids are created during this process. Computerised rig telemetry  is used in both drilling phase and concreting phase to assist the rig operator in forming the pile. 

5. Once concrete is placed and arisings removed from the pile position, the pile cage is plunged lowered into the wet concrete. 

Computerised rig telemetry provides continuous data during the drilling phase and concreting phase in order to maintain a level of quality and workmanship.

• Able to construct piles into highly stratified layers of soil comprising very resistant layers
• As a single pile or as an element of a piled wall (contiguous and  secant piled walls)  
• As an alternative for large diameter bored piles
• Infrastructure and industrial projects

• In vibration sensitive areas: no vibration is induced as the pile is formed by a hydraulic boring technique as opposed to a percussive element. 
• In a noise-sensitive environment: low noise level generated compared to other methods of piling.
• The concrete used to form the pile has a high energy input to make the cement, but this can be off-set by the use of ground blast furnace slag as a cement replacement (which would otherwise be a waste product). 
• Removal of soil from the job site (CFA piling is a ‘replacement’ technique and creates pile spoil which will require disposal)
• A dry stable, and level working platform is required.