What You Should Know About Soldier Piles
What Is a Soldier Pile?
A soldier pile is a common retaining wall strategy in which H-shaped steel beams (“piles”) are drilled deep into the earth at regular intervals — usually 2 to 4 yards apart. In between each vertical pile, horizontal supports fill the gap, helping to spread the load.
Known as “lagging walls,” these horizontal supports are most often made from precast concrete panels, steel girders or pressure-treated timber.
Where Soldier Piles Are Used
Built in successive stages, soldier piles and lagging are ideally suited for both commercial and residential use for the following:
- Home construction
- Foundation repairs
- Archaeological digs
When lagging walls require additional support, it is possible to use bracing, anchors or tiebacks. In more extreme cases, retention wall specialists might use “whales” — i.e. reinforced steel beams that are drilled into the lagging and extend diagonally into the compacted dirt on the other side of the wall.
When Is a Soldier Pile and Lagging Installation Most Appropriate?
Soldier piles offer a number of advantages over conventional retaining wall and soil stabilization approaches, including:
1. Cost
By far, the biggest benefit is affordability. Even when using heavily reinforced materials, soldier piles are considerably less expensive than other retaining wall options. This is especially attractive given that excavations are, by their very nature, temporary.
2. Speed
Lagging walls are also relatively easy to construct, making them ideal for short-term projects.
3. Flexibility
Builders have absolute control over the spacing and layout of all materials used. This makes last-minute adjustments much easier during the construction process.
4. Soil Limitations
Certain soil varieties preclude the use of more conventional retaining wall strategies — especially when dealing with consolidated clay and soil types that are easy to drain.
5. Noise and Disturbance
Although installing soldier piles is a labor-intensive activity, the actual process is relatively quiet — at least compared to other retaining wall solutions. Both the vibrations and noise are minimal, which can be a huge selling point when working in residential areas.
When Is a Soldier Pile and Lagging Installation NOT Appropriate?
Despite these advantages of soldier piles and lagging, this solution is not always suitable for every project.
When dealing with sand or soft clays, it is usually better to employ one of the other earth-retention techniques listed above. Soldier piles can withstand tremendous pressure, but only when properly drilled into compact dirt.
There are also size limitations as well. Although soldier pile and lagging installations can extend indefinitely along the horizontal plane, they become less stable when built higher than 4 to 6 yards above the ground. It’s possible to get around this by inserting piles more closely together. However, using these extra materials can quickly erode whatever cost advantages soldier piles offer.
Additional Considerations
Constructing this type of retaining wall is a reasonably straightforward process, but it is not a DIY job— even when used on a limited basis.
Before breaking ground, an experienced professional must conduct detailed soil studies in addition to structural load analyses. Moreover, the equipment used is highly specialized, requiring extensive training, and in some states, licensing and certification.
Failure to properly calibrate a retaining wall can easily lead to personal injury or extensive property damage. In extreme cases, poorly constructed soldier piles can even result in death.
This warning also applies to the deconstruction process. Once the excavation is complete, you should never try to remove horizontal lagging or vertical piles unless closely supervised.
Do You Need Help with Soldier Piles and Lagging?
At Foundation Repair Services, we specialize in a broad range of geotechnical issues and soil stabilization solutions. Contact us today if you need help building or removing retaining walls on your property.
If Soldier Piles are Not a Retaining Wall Solution for You, There are Other Options
Soldier piles are only one of many countless retaining wall options available. Some of the more popular solutions include:
- Concrete
- Anchored
- Counterfort
- Gravity
- Sheet piling
There also exist numerous earth-retention techniques that, when used in isolation or in tandem with the above, offer the same soil stabilization benefits. Common solutions include:
- Gabion mesh
- Soil nailing
- Cellular confinement
- Soil strengthening
- Rock drape
- Shotcrete facing
- TECCO mesh
Foundation Repair can help. Give us a call today at (704) 545-0206.