Piling rigs with CFA SYSTEM are used for make fondation piles, where the terrain is very crumbly and there is risk of landslide inside the hole.
In this case there isn't kelly bar but there is a CONTINUOUS AUGER, in this way avoid the risk of the walls of the hole collapsing inside.
Infact, once the depth required by the project has been reached, the auger is extracted with the soil retained between the spirals and at the same time
the concrete is pumped under pressure inside the CONTINUOUS AUGER. The concrete thus flows out of the lower part of the auger, after is possibible to put inside the metal cage.
Usually drilling rigs with CFA can make hole from Ø400mm to Ø1200mm, based on machine's power.
In addition to these used drilling rig, we have other availability.