On average, 35 construction workers are killed every year in excavation accidents. This is often the result of cave-ins due to poor soil stabilization methods.
Fortunately, there are a number of things a company or crew can do to ensure the soil in a worksite remains stable enough for heavy machinery to operate without increasing the risk of cave-ins.
We’re going to look at just a few of those methods so you can see what options you have available as a worker, foreman, or business owner. Keep reading to learn more about the methods and materials you can use to stabilize the soil.
Soil Stabilization Materials
First, we’re going to go over some of the materials used for soil stabilization. These may be used with the various methods that will be discussed later.
Slaked lime is most often used in the stabilization of subgrades and road bases, particularly in soil that is clay-like or highly plastic. As it’s added, it strengthens the soil to make it more stable.
Lime also helps to remove water from the soil which allows it to compact more.
One of the most popular options for stabilizing soil is cement. Once the soil has been mixed with cement, it’s known as soil cement. This material can be used in a variety of soil types, making it extremely versatile.
Often, other materials such as lime, sodium sulfate, or fly ash are added to the cement and soil to improve stabilization. These additives are chosen based on the type of soil in question.
Two examples of bituminous materials are tar and asphalt. These help the soil cohere, which improves stability and reduces water absorption. In turn, these things keep soil from eroding away.
The four stabilization methods used with bitumen are:
Which method is used depends on the type of soil being amended.
4. Chemical Compounds
While there are many chemicals that can be added to the soil for improved stability, the three most popular are:
All of these work in similar ways and help the soil to compact, making it more stable. They do this by increasing the water retention of the soil to help individual particles stick together better.
There are two drawbacks to adding chemicals for stabilization—first, they have to be applied several times because of chemical loss through leaching. Second, they must reach certain levels of humidity during application to be effective. Make sure you keep these things in mind when choosing to chemically stabilize your soil.
Fabrics used in the building up of soil are known as geotextiles. They are porous and come in a wide variety of options depending on what type of project you’re doing and what type of soil you’re working with.
One example is the EnviroGrid made by Geo Products. They have one of the best soil stabilization methods available today. The EnviroGrid is a series of heavy-duty cells that prevent the lateral movement of your filler material.
These also have excellent drainage so they can be used even in wet areas without fear of soil erosion from rain or groundwater. It’s also typically less expensive than bringing in additional materials needed to stabilize the ground.
Another advantage of using geotextiles is that there’s no fear of them eroding away over time. Once they are in place, they will stay there, offering a long-term solution for soil stabilization.
Soil Stabilization Methods
Now let’s take a look at some of the methods you can use to stabilize soil to prevent cave-ins and other accidents in the construction site.
1. Mixing Materials
By far the most common method for soil stabilization is mixing in the stabilizing material. Care must be taken to mix the correct percentage of additive for the amount of soil you have.
Soil depth is another concern. If you don’t have enough depth, the materials won’t be able to do their job and stability may still be an issue. Looser earth will require a deeper mixture of stabilizing materials.
As we already touched upon, different materials work best with different types of soil. For that reason, it’s essential to accurately identify the type of soil being worked with so the correct material can be used.
The cost can be prohibitive for this method when a lot of material is needed to provide the necessary amount of compaction for stability. This is in part because these materials typically need to be transported to the construction site.
A more expensive option for soil stabilization is known as grouting. This is most often used to reach areas of earth which are buried, making it difficult or impossible to mix materials into it.
There are several types of grouting methods which may be used, including:
One of these stabilizers is injected into the soil where it’s allowed to permeate and mix enough to create a stronger and more compacted area.
While this method works for most soil types, it does not work for clay-like soils because of clay’s low permeability. Grouting is also best in small areas because of the limited ability to add stabilizers to the soil.
3. Electrical Stabilization
Another expensive form of soil stabilization that isn’t used as often is electrical stabilization. This is almost exclusively used in clay-like soils and can also be referred to as electroosmosis.
Electrical stabilization of soil works by inserting metal electrodes into the earth. Then, a direct current is run through them and water moves towards one of the electrodes, most often the cathode.
As water is removed from the soil, it is better able to be compacted which allows it to provide a more sturdy foundation for construction vehicles.
Want More Construction and Design Tips?
Now you know some of the best soil stabilization methods and materials you can use in nearly any construction site to ensure the safety of workers and equipment.