Secant Pile wall A Secant Piled Wall is a retaining wall constructed for ground retention prior to excavation. The wall is formed by constructing alternating primary (female) and secondary (male) piles where the secondary piles partially cut into either side of the primary piles in order to form a continuous impervious structure. Secant walls are frequently used to as an alternative to Diaphragm walls where obstructions are anticipated, or in urban basement projects where space is limited. In co