| Starsol Pile
The Starsol
pile, developed by Soletanche SA, introduces a new concept to the construction
and quality control of CFA piles.
A powerful
rotation head, operated by a compact hydraulic motor, drives a hollow
auger and a tremie pipe simultaneously.
The auger and pipe are fitted with earth-cutting tools at the base. This
tool is screwed into the ground at high speed. It is also possible to
penetrate into dense materials.
A special
concreting system is used, which has the advantages of both classic concrete
casting and concreting under pressure. This is achieved by two openings,
situated laterally in the base of the tremie pipe. The grouting volume
and grouting pressure are permanently monitored and controlled. A special
scraping mechanism clears the spoils automatically as the tremie pipe
is raised.
The steel
reinforcement cage can be put in place at the same time as concreting
is carried out. The usual diameter of the pile is 0.4 - 1.0 m and the
maximum depth is approximately 20 meters.
Execution
sequence of a Starsol pile:
- Drilling
by rotation, the auger and the tremie pipe turn and drill together.
- Drilling
completed: the tremie pipe is clamped in position.
- The auger
is raised a few centimeters, opening two holes on the tip of the tremie
pipe.
- By means
of the tremie pipe, the concrete is injected to the base of the drill
hole. The auger is raised slowly as concreting continues.
- When the
tremie pipe has been withdrawn entirely, it is removed together with
the auger.
- The spoil
stuck on the flanges of the auger is scraped off, using an automatic
scraper.
- After
clearing the spoils, the reinforcement cage is put in place.
- The pile
is completed.
Advantages
of the Starsol pile:
- No temporary
bore hole support is needed, also avoiding the risk of caving-in of
bore hole in soft ground
- Easy penetration
through stiff soils and soft rock
- Possibility
of anchoring the pile in hard or semi-hard layers
- Concreting
can start without raising the auger.
- The concrete
shaft is cast under pressure.
- Concrete
is poured using a tremie pipe, which assures high concrete quality in
the pile shaft.
- Permanent
control of the concrete pressure and concrete volume
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