Secant Pile Wall

1. Form a 'guidewall' with predetermined spacing to accurately position the secant pile prior to drilling operations.
2. Drill and cast a series of female (unreinforced) piles formed in soft or firm concrete.
3. Drill the corresponding series of male piles through the previously cast female piles utilising the casing or heavy duty augers to cut the required secant male pile to design depth. 
male piles through the previously cast female piles with the required design intersect utilising the casing to cut the required secant
4. Cast the male piles with full reinforcement cage (and withdraw the casing, if used) to allow the concrete in the male piles to flow and bond with the existing concrete of the previously cast female piles.
5. Install a capping beam to tie piles together; ensuring the wall acts as a monolithic structure.
6. Excavate soil in from in front of the wall to allow the secant wall to retain the soil behind.
7. Install temporary and/or permanent propping where design requires.  

(Similar to Contiguous Piled Walls, with the added benefit of temporary water and fines retention)  

•  New basement structures, especially in urban areas.
• Additional support for highways subject to embankment slippage (slope stability).
• Implemented as permanent earth retaining structures along road and railway lines in excavations.
• Bridge abutments carrying horizontal.
• Embankment cuttings

Secant walls are ideal for new basement construction, particularly in built up areas where noise and vibration would be a problem, and where soil and water retention are required.

Secant walls can be installed without the noise and vibration associated with driven sheet piles enabling high capacity retaining structures to be constructed adjacent to existing buildings which may be sensitive to noise and vibration.