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Soil nailing is a technique which is used to reinforce soil. It can be used in a wide variety of settings for both permanent and temporary retaining walls among other projects. This procedure usually requires a consultation with a soil engineer to confirm that an area is a good candidate for soil nailing and it is performed by a firm which specializes in this type of work. Inexperienced contractors and companies can make mistakes which may turn out to be costly.
This technique was developed in the 1970s and appears to have originated in France. In soil nailing, the slope or wall to be stabilized is predrilled. Then, long steel rods which may be coated with anticorrosives if the soil contains corrosive material are inserted and grouted into place. The rods stabilize the soil and act to hold it in place. Finally, a covering layer is applied to fix the rods in place and add stability.
There are a number of advantages to soil nailing, when it is a technique which can be safely used. It can be done in very tight spaces, which can be useful when there is limited room to work at a site or when construction abuts another property line. Soil nailing enables projects where they might otherwise be difficult to execute. In addition, it can follow unusual and tight curves and corners safely, and it can provide stability and shoring from the top of a wall to the bottom, allowing people to secure soil as they dig.
Once the soil nailing process is complete, one of the most common methods for securing the reinforcing rods is to apply shotcrete to the wall. Construction workers can also construct a green or living wall and utilize other wall options as well, depending on the setting. The subsequent retaining wall may be temporary in nature to allow people to work on a site, or it may be a permanent part of a project.
Soil nailing is not necessarily an option for a job and it is important to have the site evaluated by an engineer to confirm that it will be appropriate. If an engineer agrees that the technique is suitable and safe, a plan for the process can be developed so that an experienced firm can come in and do the job. Specialized equipment is used for sail nailing, including tractor attachments for drilling and placing the steel rods.
If you live on a hill, soil nailing can be a great way to improve slope stability. My uncle has a gorgeous house on top of a rather steep hill, and he had some workers come in and build a retaining wall at the base of his property to prevent erosion.
They actually drove long rods into the earth to secure the wall. Once it was finished, my uncle planted various deep-rooted bushes along the top of it to further secure the soil.
The project was rather costly, but he had already retired and needed a way to spend some of his savings. Soil nailing isn't something I would ever be able to afford, but it is very effective.