Secant piles are sturdy and inflexible systems that offer both groundwater barrier walls and earth retention solutions. In the construction of secant pile walls, a series of primary and secondary overlapping shafts are drilled in alternate fashion, forming a continuous wall. The concrete used in the shafts could be exclusively low-strength, high-strength, or a mix of primary low-strength and secondary high-strength shafts. Steel piles or reinforcing steel are commonly used in the secondary shafts. Moreover, unreinforced high-strength shafts can also be constructed in a self-standing circular frame, frequently used for tunnel access shafts.
Secant pile walls are considerably leak-proof therefore, they are effective in controlling the seepage of groundwater into an excavation site and minimizing drainage outside the excavation. Furthermore, secant walls are inherently rigid, making them an ideal choice when sensitive structures are located behind the wall.
A key benefit of using secant piles for cutoff wall construction is the capacity of Schnabel’s high-powered drilling rigs. These can confront hard-drilling conditions while casing the drill hole at the same time, allowing for the advancement of cased holes through man-made and natural obstacles such as cobbles, boulders, and reinforced concrete.