What is secant Pile?
A secant pile wall consists of overlapping (secant) piles to form structural or cutoff walls and achieve the required water tightness. The design can incorporate steel bar or beams for reinforcement and anchors can provide additional lateral support, if needed.
How are secant piles installed?
The secant piles are reinforced with either steel rebar or with steel beams and are constructed by augering. Primary piles are installed first with secondary piles constructed in between primary piles once the latter gain sufficient strength. Pile overlap is typically in the order of 8 cm.
What is the difference between contiguous piles and secant piles?
Concrete @ your Fingertips The piles may be constructed so that they virtually touch each other (contiguous). The gaps between the piles can be grouted to form a watertight retaining wall. Alternatively (secant piles) every other pile may be constructed, with their centres less than two diameters apart.
What are Secant piles made of?
Secant pile walls are formed by constructing reinforced concrete piles that interlock, and are often used as a cost-effective solution when short-term water retention is required. Secant piles are reinforced with either steel rebar or steel beams.
Why are Secant pile wall used?
A Secant Piled Wall is a retaining wall constructed for ground retention prior to excavation. The wall is formed by constructing alternating primary (female) and secondary (male) piles where the secondary piles partially cut into either side of the primary piles in order to form a continuous impervious structure.
How deep should a pile be driven?
Usual depths for concrete precast piles range from a few meters to around 30 m, but under special circumstances piles have been driven down to 150 m! Steel circular piles in offshore works can go much deeper.
What is a CFA bored piles?
Deep foundations Continuous flight auger piles (CFA) are cast-in-place piles, using a single continuous hollow stemed auger. Vibration free and low noise, this environmentally friendly piling system is ideally suited to installation in unstable soil conditions and urban environments.
What is a king pile?
1. A pile along the center line of a wide trench which supports timbers that run to it from both sides of an excavation. 2. A pile which provides added support for a precast concrete or sheet steel pile wall.
What is a contiguous pile wall?
Contiguous pile walls consist of piles arranged in a line typically with a 150mm gap between the piles. Where required the soil between the piles can be stabilised using grouting techniques if necessary, either before or after pile installation.