Continuous flight auger piles (CFA) are cast-in-place piles, using a single continuous hollow stemed auger. Vibration free and low noise, this environmentally friendly piling system is ideally suited to installation in unstable soil conditions and urban environments.

Keller has Australia’s largest fleet of high capacity CFA rigs which has made us the leader in this field. Our technology and methods enable us to construct CFA piles with higher load capacities and to great depths.

Keller rig performing CFA piling

Common uses

Provide structural support
Provide earth retention, especially on site boundaries or close to adjacent buildings
Prevent landslides or protect existing buildings and are often combined with other techniques such as ground anchors or soil nails
Infrastructure projects such as tunnelling, road or bridge construction as well as flood protection

Process

The auger is drilled into the soil and/or rock to the design depth in a single pass. Once the design depth/criteria has been achieved the auger containing the drilled material is then slowly removed as concrete or grout is pumped through the hollow stem. The concrete pressure and volume must be carefully controlled to construct a continuous pile without defects. Reinforcing steel is then lowered into the wet column of concrete.

The finished foundation element resists compressive, uplift, and lateral loads. Originally introduced to address saturated unstable ground conditions, modern CFA equipment represents a cost efficient foundation solution in most soil conditions.

Advantages

Resists compressive, uplift, and lateral loads
A cost efficient foundation solution
Can be installed in most soil conditions such as sands, clays, silts, gravels and soft rock
Can achieve pile depths in excess of 30m + and with various diameters of 300 mm to 1000mm+
Low noise level and no vibration and low noise level so ideal in built-up areas with weak soil conditions and high levels of ground water
Compared to bored piles, construction is very quick as temporary casings or support systems are not required

Quality assurance

Keller deliver consistent high quality results whilst constructing CFA piles ultilising real time on board & remote monitoring of telemetry of all the functions governing the quality of the pile construction. Our experienced site teams and advanced onboard monitoring systems combine to give us the confidence in our engineering control and understanding of the ground and process to regularly install CFA piles to greater than 25m deep, and up to 52m which is the deepest CFA pile installed in Australia.

In addition our Federal Safety Commission (FSC)accreditation, company standards, processes, policies and procedures have been specifically developed to ensure consistent excellent project delivery.  Within all industry sectors Keller works strictly to Australian Standards along with the relevant Project or Industry Specifications (DTMR, RMS, VIC Roads, Main Roads WA etc).  Keller offer fully qualified in house design via certified engineers that can deliver quality piling and ground improvement solutions.  Our design and engineering certification capability includes offering static tests, pile integrity testing, thermal integrity profiling, dynamic pile testing, inclinometer testing, geotechnical inspection, and comprehensive propping/bracing and anchor design to complete the full QA package.