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This type of deep foundation is currently by far the most widely used in the world.
SEFI-INTRAFOR produces several types of piles.
None of them provides a universal solution, but each type is designed to meet specific requirements.
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Keller's Augercast Continuous Flight Auger (CFA) piling system provides a quiet low vibration form of piling that is ideal for providing foundation support in built-up or environmentally sensitive areas.
Keller's CFA rigs can construct piles in most soils including sands, gravels, silts, clays, chalk and weak bedrock, in high water tables without the need for temporary support systems.
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Covered in the New Spanish Technical Code for Building (CTE-2006) as rotation displacement piles, the Omega pile driving system is based on rotation and pushing the head of the displacement auger when driving it and rotating and pulling the tool when extracting it. Piles are installed in a total absence of vibration and produce sideways displacement of the soil, thereby compacting it and avoiding the need to remove debris.
Above the maximum diameter of the head, horizontal propellers and suitable tilt of the upper angle produce a second displacement of the soil during the extraction process and concreting. In this stage, the controlled pressure of the concrete injected through the centre pipe induces a third displacement and ensures perfect adherence of the pile with the ground.
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Some very heavy structures (high rise towers, industrial buildings) need foundation piles which can each bear a load of several thousand tonnes. The solution lies in increasing the cross sectional area of the foundation, using multiform piles or circular piles up to 3 metres in diameter. If the ground does not display sufficient strength, the piles may be belled out (under-reamed) at the bottom.
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Rotation with recoverable steel casing
In all types of ground (exept large boulder or blocks)
Minimum concrete consumption,most usual diameters :650-2200mm
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Bored Piles are circular piles made of concrete and steel being installed in the soil by various drilling methods. They divert high structural loads into deeper, stronger soils, form stringed together a retaining wall for excavation pits or terraces remove obstacles in the soil or block ground water below the surface. Depending on the application length, diameter, material, formation, and placing of the individual piles can be adapted.
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Drilled piles are often used in 'critical ground' where there is a risk of subsidence. A drilled pile is also used when noise pollution has to be avoided. In addition a drilled pile is used to 'drill out' another pile. Advantage: vibration free and fully ground penetrating. Disadvantage: the costs of drilled piles are higher than those of prefab piles.
Drilled piles were used in the construction of the Goes council offices. The ground turned out to be rock hard because of the fine soil layers containing shells, silt and very fine sand. Because of the central location in the town of Goes drilled piles had to be used for the foundations in order to keep the nuisance to a minimum.
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TRELICON technology joins the advantages of fixed piles with the versatility of application of drilled piles. A perfect method for projects in urban centres, as it eliminates vibration and disturbance to adjacent structures and reduces noise emissions. TRELICON piles make it possible to avoid decompressing the soil and using bentonite mud for drilling. This greatly simplifies the disposal of debris. Thanks to its constant technical improvement, this technology has significantly broadened its fields of application, allowing for a much wider range of diameters and lengths.
Operating specifications
The operating phases entail digging the pile by driving a continuous blade assembled on a central hollow pipe. At the end of the digging phases, extraction of the blade occurs at the same time concrete is poured by pumping from inside the same blade. When required, piles may be reinforced for their entire length with reinforcement cages inserted in the still wet concrete.
Technical data
Pile diameter: 400 to 1400 mm
Depth: 25 ÷ 36 meters (with blade loader) depending on soil diameter and consistency.
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The Continuous Flight Auger (CFA) system is well known as a rapid and cost effective open site method of constructing load bearing and retaining structure piles where the appropriate ground conditions exist. This makes it suited to many construction projects and particularly for sensitive sites, where it provides a quiet and vibration free piling technique.
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"Pious realized by means of a drill with hollow axis screwed in the ground without notable extraction of the ground, the drill is then extracted from the ground without unscrewing while, simultaneously, the concrete is injected by the hollow axis of the drill."
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The improvement of poor soils by depth vibrators is an innovation of Keller. For the treatment of non-cohesive and cohesive soil formations different types of depth vibrators and various techniques are available. Together with the different methods of soil improvement a wide range of pile foundations and similar foundation techniques are available.
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Drilled piles, temporarily tubed
The drilling of this type of pile is carried out with l%u2019abri d%u2019un provisional casing so d%u2019éviter any landslide in the future deep foundation. The tools for drilling are adapted to each type of ground/rock so d%u2019optimizer the realization of the pile. Once the finished pile, its liaisonnement with the superstructure is facilitated by the precision of its establishment and the presence d%u2019une cage d%u2019armature installation at the desired and perfectly centered dimension.
The advantages of this type of pile are:
%u2022 drilling in n%u2019importe which type of ground
%u2022 obtaining the cut of ground with l%u2019endroit of the pile
%u2022 compressing quasi no one
%u2022 precise establishment
%u2022 cage d%u2019armature installation at the dimension desired and perfectly coated in the concrete
%u2022 quality of l%u2019élément finished
%u2022 possibility of checking d%u2019exécution quality of the pile a posteriori (sonic control, coring...)
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Definition:
pile drilled under provisional lining and water overpressure (if necessary), concreted with a plunger tube in order to avoid the segregation of the concrete
Properties:
standard diameter of the drilled piles: 600mm, 750mm, 900mm, 1070mm, 1280mm or 1500mm
possible not-concreted length
bearing capacity until 12500kN
possibility of injected the barrel and the point
drainage of grounds necessary
without vibrations
Scope of application:
vertical, horizontal high loads and/or in inflection
sat or embedding in hard or rock ground
in the event of obstacles in basement (old foundations, concrete) limiting other techniques
level of sitted very deep (until >50m).
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Realization of drilled piles tubed temporarily near overhead lines électifiés
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