Continuous flight auger piling is a specific type of piling which falls into the broader category of bored piling. Bored piling is carried out by first boring a hole in the ground for the pile to be installed in. This is different to screw piling and drive piling which have their own method of insertion for the piles. For all bored piling, bore holes are first created and then filled with liquid cement to allow it to set in place, this is done with the assistance of steel tubing to line the hole which can be removed at the end for reuse or left in place as an extra layer of reinforcement. Continuous flight auger piling takes a different approach to this method.
A continuous flight auger is a type of large-scale rotary piling equipment which will drill (or bore) the hole for the piles to be set in. Using a continuous flight auger is the quietest form of piling and produces the least vibrations, so is perfect for residential areas or any other sites where reducing noise pollution is vital. Continuous flight auger piling is conducted by first drilling a continuous flight auger into the ground to the desired depth. Once the desired depth is reached the temporary plug designed to prevent soil from entering the bore hole is removed, leaving the hollow auger open for concrete.
Concrete or grout must then be added to the hole and is injected through the auger itself, pumped down the hollow stem. The auger is reinserted for this process and is extracted as the concrete is injected. This is why it is known as continuous flight auger piling – as the auger is removed the foundational material is added, creating a continuous smooth installation effect until the surface level is reached.
With continuous flight auger piling, the most important aspect is balance. The pressure of the grout or concrete must be high enough to ensure the bore hole is filled completely but not so high as to disturb the surrounding soil. The auger must also not be extracted too quickly as this can cause soil to flood the pile shaft.