When it comes to stabilizing slopes or supporting excavations, soil nailing and retaining walls are two common methods. But which one should you choose? Choosing the right support system depends on the project’s specific requirements, location, and goals. This article will provide an in-depth comparison of these two methods, helping you determine the best choice for your project.

Soil Nailing and Retaining Walls

Soil Nail Wall Specializing in retaining wall construction, Schnabel provides customized solutions for different project conditions.

Before we cover each method in detail, let’s briefly explore what soil nailing and retaining walls are. Soil nailing is a technique where the soil is reinforced with steel nails and usually involves spraying concrete onto the excavated slopes to stabilize the area. On the other hand, retaining walls are structures that hold back soil, preventing shifts and landslides.

  • Soil Nailing Method: Soil nailing involves drilling holes into a slope and inserting steel bars or “nails” to stabilize the slope. This method is typically used in projects where quick stabilization is needed. The nails are usually installed at an angle, and once they are in place, the slope is often covered with a layer of shotcrete.  One of the best benefits of soil nailing is its adaptability as it can be used in a range of soil conditions and types. It’s particularly beneficial in projects where space is limited. The technique also allows for work on uneven and steep slopes without the need for extensive excavation.
  • Retaining Wall Method: Retaining walls are constructed using various materials like concrete, stone, or wood, and serve as a barricade against shifting soil. The walls are usually built perpendicular to the ground. Retaining walls are commonly used in projects that require long-term stabilization solutions, thanks to their durability. They are ideal for highways, and other infrastructure projects needing reliable soil stabilization.

Comparison of Both Methods

  • Pros and Cons of Soil Nailing: One of the main advantages of soil nailing is its cost-effectiveness. The materials and labor involved are generally less expensive compared to retaining walls. Soil nailing is also quicker to implement, offering rapid stabilization. Despite its advantages, soil nailing has some limitations. It may not be the best solution for areas with soft soil conditions or where groundwater issues are present.
  • Pros and Cons of Retaining Walls: They require substantial space for installation, which can be a limitation in projects where space is limited.

Cost Comparison: Soil Nailing vs. Retaining Walls

When comparing costs, both initial expenses and long-term maintenance should be considered. Soil nailing typically has a lower initial cost due to the minimal materials needed and the faster implementation time, which also helps reduce labor costs.

In contrast, retaining walls require a higher initial investment because of the cost of materials such as concrete and stone, and the construction process tends to be more labor-intensive. However, retaining walls generally have lower long-term maintenance costs compared to soil nailing.

Permanent Retaining Wall

Relevant Case Studies

  • M&T Bank Stadium: For this project, Gilbane Construction Company contracted with Schnabel to design and build an excavation shoring system for the below-grade renovations at M&T Bank Stadium, home of the Baltimore Ravens. As part of the work, Schnabel installed more than 14,000 square feet of permanent shotcrete foundation walls, reinforced with over 700 soil nails. Learn more about this project here.
  • I-495 Hot Lanes: For this project, the Virginia Department of Transportation contracted Schnabel to design and install permanent retaining walls along a fourteen-mile section of I-495 as part of a highway widening effort to reduce congestion. Schnabel constructed seven tieback walls, twenty-two cantilever walls, and one secant pile wall. Additionally, seventeen of the walls were equipped with sound barriers above the retaining walls. Learn more about this project here.

Conclusion: Which Method is Better?

The best choice depends on the specific needs of the project. Soil nailing offers an efficient, cost-effective solution for temporary stabilization and projects with limited space, while retaining walls provide long-term durability and aesthetic value, making them ideal for large-scale projects. Both methods have their advantages and drawbacks, so the best choice will ultimately depend on the unique requirements of the site.

With over 65 years of experience, Schnabel is a trusted provider of both soil nailing and retaining wall solutions for even the most challenging construction projects. Our team has successfully designed and constructed soil nail walls and permanent retaining walls for clients across the industry. To learn more about Schnabel’s advanced earth retention solutions, contact one of our regional offices today.