There are many benefits to secant pile walls, including increased construction alignment flexibility, increased wall stiffness compared to sheet piles, the fact they can be installed in difficult ground (cobbles/boulders), and they can be used in high water table conditions with little dewatering.
Applications for secant pile walls include shoring, large diameter access shafts, large storage tanks, etc.
The walls are formed by constructing intersecting reinforced concrete piles. The piles are reinforced with either steel rebar or steel beams and are constructed by drilling open hole, slurry drilling, continuous flight auger drilling, or using the temporary cased secant pile method.
Primary piles are installed first with secondary piles constructed in between the primary piles once the latter gain sufficient strength. Pile overlap is usually three inches.