Secant Pile Walls

What are Secant Pile Walls?

Aarsleff Ground Engineering are a choice Secant Pile Wall contractor, designing and delivering operational excellence to create value-engineered solutions bespoke to your site.

Secant Pile Walls are formed by constructing intersecting reinforced concrete piles. 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.  They are constructed when resistance to groundwater is required using the CFA technique or the cased CFA technology.

What are Secant Pile Walls for?

Secant Pile Walls are usually installed as retaining structures and support systems for deep foundations, retaining elements and at the same time load-bearing walls and deep foundations for engineering constructions (e.g. walls and foundations of underground storeys, stand-alone and framed bridgeheads, etc.).

How are Secant Pile Walls constructed?

Secant Pile Walls can be constructed using the CFA or the Cased CFA technology, consisting of reinforced piles with the gaps between them filled with

  • columns made of low-strength material of 1-3 MPa (concrete or mortar, usually with bentonite), spaced approx. 620-670mm for drilling diameter of 470-500mm. This solution ensures resistance to groundwater (temporary support), but does not guarantee permanent water resistance. In order to ensure permanent water resistance, additional liners or sealing agents are required
  •  Full-strength concrete piles with prolonged binding time, spaced approx. 400mm for a drilling diameter of 500mm. This solution also ensures long-term water resistance and is widely used as a support system for deep excavations with a pile wall constructed on circular plane, since waling beams and/or struts are not required.
What are male and female piles?

The primary piles/columns cast first are called female or soft. The reinforced load bearing piles are drilled to intersect the female piles/columns and are called male or hard.

How about a Cantilever pile wall?

Cantilever pile walls can be used for protecting land faults up to 5m high or, if using anchors or struts, up to 20m high. Secant pile walls allow for protecting land faults up to 5-6m or, if using anchors or struts, up to 25m high. Standard rake of installed pile wall does not exceed 1:75, however, under special monitoring the rake can be reduced to 1:125, and in some cases, even to 1:200 (for secant pile walls made of hard piles and installed using the CCFA technology).

What are the main advantages of a secant pile wall?

  • Increased wall stiffness compared to sheet piles
  • Can be installed in difficult ground (cobbles/boulders)
  • Less noisy construction
  • Greater retained heights
  • Axial loading

 

Get a quote

For more information about Aarsleff Ground Engineering or to send in your enquiry,
call 01636 611140 and speak to an expert member of our team today.

A leading UK ground engineering specialist, focusing on multi-discipline excellence and value engineering. We design and deliver some of the UK’s largest ground engineering projects.

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1947. Central Jutland, Denmark. Per Aarsleff borrowed 10,000 Danish Kroner from his father’s life insurance, bought an excavator, and founded Northern Europe’s leading contracting company.

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