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Techniques

Secant Piles 

Secant walls are formed by an interlocking system of soft unreinforced piles (female) and reinforced structural concrete piles (male). The design is to restrict water ingress into excavations below the groundwater table. Using a guidewall ,with scallop formers installed, indicates the pile positions also eliminating the need for a full time engineer marking pile centres. The piles are installed in sequence with the softer female piles being installed first and males following to create the interlock. Though not 100% water proofing the reduction in water ingress is hugely manageable.

Temporary cased bored piles

Temporary cased bored piles are normally used where deep or full depth steel is required such as Contiguous or Secant walls. Temporary casings are offered into the grounds until penetrating stiff soils, such as clay, and then the auger is drilled to designed depth. The steel is then introduced, concrete poured and casings removed, topping up concrete due to the slump experienced through the extraction. Other benefits from temporary cased piles include pouring concrete to the desired COL saving the client time and money in breaking down excess concrete. Verticality is also proven to be much more accurate with this method.

SFA / CFA (Hollow Stem)

Sectional/Continuous flight auger is used to form piles through soft/loose grounds. This method consists of drilling the auger to the designed depth and being withdrawn slowly whilst the concrete is pumped through the hollow stem into the pile. The reinforcement is then introduced once the auger has been fully retracted

Bearing/friction piles 

Bearing Piles are designed to transmit a load, through weak soils, into a strata strong enough to accept the load. Shaca offers diameters up to 450mm and reinforced to a level determined by the pile design.