RETAINING WALLS

SECANT & CONTIGUOUS PILE WALLS


Secant and contiguous pile walls provide effective earth retention and excavation support, especially in constrained or urban environments. Installed using Continuous Flight Auger (CFA) techniques, these systems offer a fast, low-noise, and virtually vibration-free solution suitable for a wide range of ground conditions. Their efficiency and minimal disruption make them ideal for complex construction sites where precision and stability are essential

SECANT PILE WALL

Secant pile walls are formed by interlocking primary and secondary concrete piles to create a continuous barrier. Installed using the CFA method, they are ideal for water-tight earth retention and excavation support in complex ground conditions. Their low vibration and quiet installation make them well-suited for urban and sensitive environments.

Contiguous pile walls consist of closely spaced bored piles with minimal gaps, offering strong and efficient support for temporary or permanent excavations. Constructed using CFA techniques, they are a fast and cost-effective solution for projects where water ingress is not a major concern, particularly in dry or stable ground conditions.

CONTIGUOUS PILE WALLS

THE PROCESS

Both secant and contiguous walls are typically installed using Continuous Flight Auger (CFA) piling techniques:

  1. Boring: A CFA rig drills piles to the required depth using a continuous flight auger.

  2. Concrete Placement: Once the depth is reached, concrete is pumped through the hollow stem of the auger as it is gradually withdrawn.

  3. Pile Formation:

    • For contiguous walls, piles are installed at regular intervals with small gaps between them.

    • For secant walls, piles are constructed in a specific sequence—first unreinforced (soft) primary piles, followed by reinforced (hard) secondary piles that cut into the adjacent primary ones to create a continuous interlocked wall.

  4. Reinforcement: Steel cages are inserted into the fresh concrete of designated piles as per the structural design.

  5. Finishing: The wall is trimmed or cut off to the required level at the piling platform.