Secant Pile Wall Design Examples

Operating nationwide, Schnabel is a leading design-build company that erects dependable and structurally robust secant pile walls. These walls are not only effective for excavation support but also form proficient groundwater barriers during excavations. As an example of secant pile wall designs, these strong, overlapping shafts create an uninterrupted concrete wall.

The process of drilling secant pile shafts is performed using specialized equipment that ensures the necessary precision in alignment, an essential aspect for the effectiveness of the secant pile wall. The diameter of these shafts usually ranges between 2 to 4 feet. On the other hand, tangent piles are like their secant counterparts, except their shafts merely touch each other without any overlap.

Schnabel, with its extensive experience of several decades in creating customized solutions for water and earth retention, is well-equipped to deliver secant walls that cater to your most challenging construction requirements. These examples of secant pile wall designs demonstrate Schnabel’s commitment to overcoming complex construction challenges.


Secant piles form a part of a solid, sturdy system that amalgamates earth retention with groundwater barrier walls. An exemplary procedure for secant pile wall construction involves drilling an array of primary (drilled first) and secondary (drilled second) overlapping shafts, which collectively constitutes a cohesive secant wall. The concrete content in the shafts can be either entirely low-strength or high-strength, or a mix of both, with low-strength primary and high-strength secondary shafts. Typically, steel piles or reinforcing steel is inserted into the secondary shafts. There’s also a possibility of constructing unreinforced high-strength shafts within a self-supporting circular structure, often used in access shafts leading to tunnels.

Secant pile walls showcase comparative impermeability, making them fit for controlling groundwater inflow during excavation and minimizing drawdown on the excavation perimeter. Secant walls hold significant rigidity, proving to be ideal when sensitive structures are located behind the wall.

The utilization of secant piles for cutoff wall construction has an inherent advantage owing to Schnabel’s high-torque drill rigs. These rigs have the proficiency to penetrate tough drilling conditions while casing the drill hole concurrently. With the ability to navigate through man-made and natural barriers like cobbles, boulders, and reinforced concrete, these drills are a testament to Schnabel’s innovative approach to the complexities of construction.

Furthermore, the adaptability and resilience of secant pile walls make them a go-to solution even in challenging soil conditions. These designs, with their combination of functionality and structural integrity, stand as proof of Schnabel’s dedication to delivering top-notch, cost-effective construction solutions to their clients. The deep roots of experience that Schnabel has laid down over decades in the construction industry enables them to fully realize the potential of secant pile wall technology, thereby taking the construction project one step closer to success.

In instances where challenging drilling conditions are expected, secant piles serve as an economically sound solution for constructing cutoff walls. Another added advantage of this method is its relatively lower mobilization costs when compared with other cutoff wall varieties like slurry walls and soil mix walls. To delve deeper into understanding if a secant wall is the ideal fit for your project requirements, get in touch with one of the eight regional offices of Schnabel today. Their team of seasoned professionals is dedicated to providing guidance tailored specifically to your construction project’s needs.

Always innovating new approaches to better solve old problems.

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Rondout West Branch Bypass Tunnel Shaft

Schnabel installed secant piles in a self-supporting circular ring to support the construction of a new bypass tunnel to allow water to flow under the Hudson River to New York City after an older tunnel started to leak.

secant piles

Barnes-Jewish Hospital

Schnabel designed and constructed a secant pile wall for the Barnes-Jewish Hospital Parkview Tower on the Washington University Medical Campus in St. Louis, Missouri. The perimeter secant wall served as both the permanent structural basement wall and the temporary earth-retention system for the new hospital building.

In 31 years of building deep foundation projects for Schnabel, building a 90’ deep reinforced circular shaft was one that was very challenging and deeply rewarding. Looking forward to working on the next one with our client Schiavone.
Paul Davis, Rondout West Branch Bypass Tunnel Shaft


Schnabel is the sector’s most operationally efficient Geostructural Design & Construction contractor. We optimize efficiencies by leveraging decades of experience and design/build expertise to innovate processes and approaches that are consistently proven to deliver optimal outcomes for our clients.