Secant and tangent walls are constructed from a sequence of bored holes either overlapping (secant) or adjacent to (tangent) each other. Both methods create a continuous concrete wall which can be used not only as support for an excavation, but also as a deep foundation. For secant pile walls, the overlap of the concrete can be an effective barrier to groundwater flow. Both types can be constructed utilizing a variety of methods including drilled shafts, drilled micropiles, soil mixing, jet grouting, and auger cast piles. While deflection is often lower than other excavation support methods, secant and tangent pile walls require much larger equipment and are often a more expensive option.
Typical Applications for Secant/Tangent Piles