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Full displacement drilling is a modified version of continuous flight auger drilling and is exclusively used for producing cast-in-place piles. The surrounding soil is only displaced and almost no drill cuttings are conveyed to the surface. Instead of a continuous auger a smooth casing is used. At the lower end the casing is fitted with a so-called displacement body.
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
The video shows various Liebherr carrier machines working with full displacement tools.
The casing is equipped with a displacement body at the lower end.
With full displacement drilling almost no drill cuttings are conveyed to the surface. The surrounding soil is only displaced.
After the casing has been drilled down it is extracted again.
During extraction the concrete is pumped through the hollow stem and exits at the lower end.
Depending on the process the reinforcement cage can be inserted either before or directly after extraction of the casing.
The drilling depth is increased when using a Kelly extension.
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.