Generally considered to be a superior product to contiguous pile walls, secant pile walls comprise interlocking piles to form a virtually watertight seal. Interlocking of the piles is necessary for excavations in granular material in water-bearing ground, where soil loss between the piles would pose significant construction problems.

These walls generally comprise the conventional 'hard-soft' form where the 'soft' low strength unreinforced piles are first installed, then the alternating 'hard', reinforced piles are scalloped into the 'soft' piles, forming the virtually watertight seal. Where possible. guide walls are utilized by Vibro-pile to ensure correct positional tolerance and wall alignment.

Alternatively, Vibro-pile's proprietary concrete mix designs and special tooling enable all the piles to be 'hard' reinforced if required, in order to maximise the load-carrying capacity of the interlocked wall, resulting in savings in economy and scale.