Drilling with Kelly

Classic bored pile system which transfers torque and vertical crowd force to drilling tools via a telescopic kelly bar.

  • Borehole wall is supported either by excess hydrostatic pressure or by drill casings
  • Installation of drill casings by rotary drive or by casing oscillators attached to the rig
  • By using different drilling tools the system can be employed in all types of soil (including bedrock)
  • Diameters 600 – 3000 mm
  • Drilling depths from 15 – 90 m

Drilling with Continuous Flight Auger (CFA)

  • The soil which is loosened at the auger tip is conveyed to the surface by the auger flight
  • Borehole wall is supported by the auger filled with drill spoil
  • Use of a crowd winch facilitates penetration into hard soil formations
  • Attaching a kelly extension increases the drilling depth by 6 – 8 m. Pile is concreted through hollow stem by means of concrete pump
  • Concrete is pumped by a concrete pump through the hollow stem of the auger while extracting the auger. Concrete feed pressure can be measured at the tip of the continuous flight auger
  • Diameters 500 – 1200 mm
  • Drilling depths from 10 – 28 m

Drilling with Cased Continuous Flight Auger (CCFA)

Drilling with Cased Continuous Flight Auger is one of the single-pass drilling techniques. During the drilling process, a continuous flight auger protected by a counter-rotating casing string conveys the drill spoil to the surface. Concrete is subsequently poured through the hollow stem of the auger. With drilling diameters of up to 600 mm, FOW counts as one of the CCFA drilling techniques.

Full Displacement Pile (FDP)

A displacement head is drilled into the soil with high torque and crowd. Displacing of the soil results in a densified skin area with increased bearing capacity. Concrete is pumped through the hollow stem. As the tool is rotated in one direction during extraction, it is possible to recompact loose side wall areas.

More information can be found in our brochure: Full Displacement Pile (FDP)