Continuous flight auger (CFA) piling is a highly versatile technique for installing foundations in a wide range of ground conditions. Fast, quiet, and virtually vibration-free, the method is ideal when working next to buildings, homes and in environmentally sensitive areas.
What is CFA piling used for?
Continuous flight auger (CFA) piles are a quick and economical solution suitable for most ground conditions and construction projects. This method is one of the quietest forms of piling which is virtually vibration free. Ideal solution for projects in urban locations where noise levels need to be kept to a minimum. CFA piles can be designed to provide both vertical, lateral and tension support.
How are CFA piles installed?
CFA piles are constructed using a continuous hollow stemmed helical auger which is rotated into the ground to the design depths. On reaching the founding level, high slump or flow concrete is pumped through the hollow stem in a controlled manner ensuring a static head while the auger is extracted simultaneously. Pile arising resulting from the process are cleared from the auger using an auger cleaner as the auger is extracted. The method of installation enables piles to be formed in water bearing strata without the need for temporary casings. The pile reinforcing cage is then inserted into the concrete.
Throughout the installation process sophisticated onboard computers monitor both the boring and concreting process. The real-time system provides the operator feedback regarding key installation parameters including auger depth, casing depth, auger revolutions, drill pressure/auger torque, strata details and water strikes observed during the boring phase. The cloud based online data portal allows engineering teams to monitor their contracts and individual pile installation from remote locations in real time.
Key capabilities
- Rig loadings: 33 – 85 tonnes
- Pile diameter: 300 – 1,200mm
- Maximum depth: 35m
- Working load: Up to 8,000kN
What are the advantages of CFA Piling?
- Fast, quiet, and virtually vibration-free
- No need for casing, bentonite, or polymers
- Cost-effective and versatile technique for most ground conditions
- Efficient and cost effective, as production rates are higher than other bored piling methods.
- Less plant and equipment required on site compared to the rotary bored method
Common Uses
- Structural foundations across all construction sectors
- Suitable for clay, weak rock and water-bearing sand, gravel, and glacial till
- Secant and contiguous piled retaining walls and can be used in conjunction with temporary props and permanent anchors
- Slope stabilisation and retention to prevent slip and landslides
- Retention for deep excavations and basements close to adjacent structures
- Working next to buildings and homes and in environmentally sensitive areas
- Used across infrastructure projects including tunnelling, road or bridge construction and flood prevention
