Continuous flight auger drilling | Liebherr deep foundation

Continuous flight auger drilling

A single-pass drilling method

CFA drilling (cast-in-place piles)

Continuous flight auger drilling belongs to the dry rotary drilling methods. It is suitable for predrilling as well as for the installation of cast-in-place piles. The soil (under certain conditions also rock) is loosened and conveyed continuously using a continuous flight auger. The borehole wall is supported by the auger flights filled with drill cuttings.

Procedure of producing a cast-in-place concrete pile with continuous flight auger drilling:

1. Positioning at the drilling point

2. Auger drilling until the final depth is reached

3. Extracting the auger and pumping in concrete

4. Pressing or vibrating in the reinforcement

5. Finished pile

Video: Continuous flight auger drilling

The video shows an LRB 125 installing cast-in-place piles using the continuous flight auger drilling method.

Drilling with continuous flight auger

The auger is drilled into the ground down to the final depth in a single continuous process.

Conveyance

During the drilling process the auger flights convey the soil to the surface.

Auger flights filled with drill cuttings

The auger flights filled with drill cuttings support the surrounding borehole wall during continuous flight auger drilling.

Kelly extension

For auger drilling the drilling depth can be increased by using Kelly bars.

Concreting

Concrete is poured in through the auger’s hollow stem as the auger is extracted.

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Drilling rig with fixed leader for drilling depths of more than 50 metres

With a lattice boom leader and crawler crane as carrier machine, cast-in-place piles of more than 50 metres in length can be produced using the CFA method.