A secant piled wall is formed by constructing alternative interlocking secondary and primary bored piles as a retaining structure providing load bearing walls and deep foundations for engineering construction.
What is a secant piled wall?
A secant pile wall is a bored pile retaining wall formed by installing interlocking primary and secondary piles to form a homogeneous continuous retaining structure incorporating a capping beam. Secant pile walls are flexible in shape and design compared to diaphragm retaining walls and offer a significant lateral strength advantage compared to that of sheet piled walls.
Secondary piles include steel reinforcing cages and high slump concrete, while the composition of primary pile can vary depending on soil type, ground water profile, retained heights, available construction time, propping arrangement, cost and design life. The following three alternatives are adopted:
- Hard / Soft – a concrete bentonite blended mix is used within primary piles
- Hard / Firm – low strength concrete is used in the primary piles
- Hard / Hard – full strength structural concrete is in primary piles
Cased secant piling offers the cost and speed benefits of CFA piling with the accuracy of rotary bored piling to create a near watertight secant piled walls.
Key capabilities:
- Rig loadings: 6–110 tonnes
- Pile diameter: 600–1,200mm
- Pile Diameter: 1,000mm cased CFA
