As part of a rigid, secure system, secant piles merge the functions of earth retention and groundwater containment walls. The construction of secant pile walls involves drilling and alternating primary (drilled first) and secondary (drilled second) shafts that overlap one another, forming an unbroken secant wall. The concrete used in the shafts could either be purely low-strength, entirely high-strength, or an amalgamation of primary low-strength and secondary high-strength shafts. Secondary shafts frequently feature steel piles or reinforcing steel. Non-reinforced high-strength shafts can also be erected in a circular layout for self-supporting purposes, a common choice for access shafts to tunnels.
Characteristically near waterproof, secant pile walls aid in controlling groundwater seepage into excavation sites and restrict external drainage. Owing to their stiffness, secant walls are a popular choice when surrounding sensitive structures.
A noticeable advantage of employing secant piles for cutoff wall construction lies in Schnabel’s high torque drilling rigs’ capability to maneuver through challenging drilling conditions whilst concurrently casing the drill hole. These drills can still proceed with casing a hole even through human-made and natural obstructions such as cobbles, boulders, and reinforced concrete.