Continuous Flight Auger (CFA) piles are constructed by drilling a hollow-stem continuous auger into the ground to the required depth. The auger provides continuous support to the borehole, eliminating the need for temporary casing or drilling fluids.
Once the design depth is reached, concrete is pumped through the hollow stem as the auger is gradually withdrawn, filling the void. Immediately after concreting, a reinforcement cage is inserted into the fresh concrete.
Originally developed for soft, sandy, or water-bearing soils, CFA piles have become widely used due to their rapid installation, low noise and vibration, and suitability for deep foundations in various ground conditions.