Secant Piled Wall
Secant Pile Walls are formed by drilling alternating primary and secondary piles where the secondary piles partially cut into either side of the primary piles in order to form a continuous impervious structure. Steel reinforcement is then installed into the secondary piles to further increase rigidity of the wall. Secant walls are frequently selected over other solutions when obstructions are anticipated, or in urban projects where space is limited. In comparison to diaphragm walls they can be flexible in shape and offer a relatively compact operation.
Secant Walls can be Hard/Soft, Hard/Firm or Hard/Hard depending on design requirements.
Hard/Soft incorporates a bentonite/cement slurry
Hard/Firm incorporates high reinforcement/low strength concrete
Hard/Hard incorporates a full strength structural concrete
Secant walls overlap which allows them to act as waterproof barriers and prevent soil intrusion.