Continuous Flight Auger (CFA) Piling
A CFA pile is formed using a long string of augers, with soil displaced via the auger flights. Piles can be drilled from 300mm to 900mm diameter to depths of up to 27m with the concrete pumped through the hollow stem of the augers as they are withdrawn from the design depth. Reinforcement cages are installed immediately after concreting and can be installed generally to lengths of up to 12.0m. Ancillary equipment will also include concrete agitators, concrete pumps, diesel bowsers and storage containers. In water bearing soils longer reinforcement cages can be installed with the aid of attendant services cranes and or cage vibrators.All our CFA rigs feature in-built computers to monitor the volume of concrete pumped as the auger is extracted. This instrumentation allows careful monitoring of pile formation, ensuring stability of the bore and integrity of the pile. Each rig is connected to a mobile network to transmit pile construction data as the pile is built.
We have a modern fleet of CFA piling rigs suited to every application, from 38T rigs for smaller access sites to 65T rigs for deep, large diameter CFA piles. These rigs have capability of constructing piles in a variety of ground conditions. CFA piling is particularly suited to piling through interbedded sequences of clays and water bearing non-cohesive strata or soft rock.
Heavy duty twin wall augers are used for contiguous and secant piling, to maintain piling tolerances and maximise the space in a basement or on a sloping site.CFA piles are generally quick to install offering the most economic cost solution for many sites. Crucially for urban and confined sites, our CFA rigs have minimal environmental impacts in terms of noise and vibration.