The cased CFA pile is a variation on the traditional CFA pile.

Cased CFA piles

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, rail or bridge construction as well as flood protection

Process

Cased CFA piles are constructed by rotating a hollow stem continuous flight auger within a temporary casing into the soil to a designated depth. The double rotary drive units for the auger and casing rotate in opposite directions, simultaneously drilling them into the ground. This allows for faster continuous drilling while the casing helps to keep the pile vertical, which is of particular importance for applications such as secant pile retaining walls. Concrete or grout is pumped through the hollow stem, maintaining static head pressure, to fill the pile drill hole as the auger and casing is slowly removed.

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 600mm to 1000mm
Low noise level and no vibration 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 support systems are not required
Superior cutting power and faster drilling compared to traditional CFA with higher construction tolerances and pile surface appearance

Quality assurance

Close control of the installation process is essential to ensure the highest quality pile construction.
All Keller CFA rigs are equipped with sensitive state-of-the-art instrumentation that monitors all aspects of CFA piling, including pile depth, auger rotation, penetration rate, concreting pressure, extraction rate and over-break. The instrumentation produces an individual quality control construction record for each pile that includes element identification, date, time and operator details.