Cased CFA combines the benefits of a rotary and a CFA solution proving particularly beneficial and effective when installing larger contiguous and secant piled retaining walls. The single flight auger allows much faster continuous drilling whilst the casing helps to keep the pile vertical, within tolerance and in the case of a secant piled wall, watertight. The rotary drive units for the casing and the augers are connected but rotate in opposite directions, simultaneously drilling them into the ground. As in a traditional CFA technique, the spoil travels up the auger string and is deposited from the top of the casing into a series of telescopic tubes safely expelling it directly into a wagon, a skip or to a holding area at ground level.
Concrete is then pumped through the hollow stem of the auger as it is retracted and the cages are installed once the pile is complete.
Our on-board software system is used to monitor and control pile construction in a similar manner to traditional CFA piling.