O-Pile walls consist of tightly interlocked pipe piles utilizing an innovative mechanical “ball-and-socket” type connector welded to the full length of the pipe to create a continuous watertight wall that can be either temporary or permanent.
Unlike other excavation support techniques such as sheetpiling and secant pile walls, O-Piles can be installed through bouldery ground conditions.
A pile guide/template is laid out on the surface to ensure verticality during installation. O-Piles are installed using rotary percussion reverse circulation drilling techniques with air/water flush and a down the hole hammer to handle boulders and obstructions.
Accurate determination of top-of-rock elevations allows the pile assembly to be prefabricated off site. This saves time in the overall installation schedule and is also advantageous where the working area is limited. The pipe pile assembly, complete with an interlock, is advanced to design depth in a single pass and can be readily embedded into sound rock. Grouting is performed inside the pipe and the annulus space to complete the cut-off.
A dedicated full-time technician is assigned to perform quality control and quality assurance. This can include pre- and post-wall installation pump tests, pile verticality checks during installation, production pile drill logs and grout logs, and permeability testing to confirm the adequacy of the cut-off wall.