The biological, chemical or mechanical adjustment of engineering properties of soil is known as soil stabilization. Soil stabilization is a technique used in civil engineering to modify and improve the engineering properties of soils. Shear strength, permeability, compressibility, durability, and plasticity are examples of these properties.
Physical or mechanical improvement is widespread, although certain schools prefer to use the term “stabilization” to refer to chemical improvements in soil qualities achieved through the use of chemical admixtures.
Soil serves as the basis for any construction project, whether it be a structure, a road, or an airfield. Furthermore, soil is an important construction material.
There are different objectives for this, which include:
The materials used in soil stabilization vary depending on the approach used. They are as follows:
Different soil stabilization methods are discussed below:
Physical procedures such as compacting or tamping with machinery like rollers or rammers fall within this category. To carry out this procedure, heavy machinery capable of applying a large compressive force is needed. This usually includes a huge compactor or, in rare cases, a crane with dropping weight.
When mechanical soil stabilization is used, the soils that are stabilized are frequently rocky and sandy soils. Mechanical stabilization is rarely the sole stabilization method due to advances in other types of soil stabilization.
While mechanical soil stabilization is not widely used, it has advantages. One advantage is that the soil particles are physically transformed, implying that no chemical changes are taking place that will eventually wear away. The method is known to be time-consuming, difficult, and expensive due to the physical modification.
As the name implies, it is dependent on the chemical reaction that occurs between the chemical/stabilizer used and the soil particles. Cement, lime, magnesium chloride, bitumen emulsion, and fly ash are a few examples that are used.
One of the most common methods of soil stabilization is lime or cement soil stabilization. This method of soil stabilization involves mixing lime or cement into the soil to boost its strength and resistance.
The usage of lime or cement to stabilize soil is frequently determined by geographical area. Some areas have easy access to lime, whereas others do not, making cement more cost-effective.
Soil stabilization with lime or cement works by binding all of the soil’s particles together, improving the strength of the soil. Because this approach necessitates the addition of cement or lime to the soil, practically all soil types are compatible with this method of soil stabilization.
Soil testing is essential to ensure that the appropriate amount of additives is applied. If only a small amount of additive is employed, the soil will not achieve the appropriate strength. If a greater amount is used, the soil may shrink or crack.
Fly ash soil stabilization is similar to lime or cement soil stabilization, however, the product employed differs. Fly ash is a byproduct of coal that is used in coal-fired power plants.
When compared to lime or cement soil stabilization, fly ash typically reduces soil stabilizing costs. Fly ash is essentially a byproduct of different manufacturing processes.
Fly ash has a significant advantage in that it is a dry additive, which is highly advantageous for high moisture soils. Being a dry additive has the disadvantage of being hard to apply, as well as posing a health risk to workers due to the powder’s inhalation risk.
Another consideration when utilizing fly ash is the curing time. While the cure period varies depending on the fly ash and soil, it is frequently longer than that of cement or lime-treated soil.
Polymers work based on a long repeating molecule, which means that soil particles bond to the molecule. Polymers are so compatible with all types of soil, ranging from sandy to clay. Because the soil particle must fit into the molecule, the size of a polymer’s molecule affects its performance on any specific soil.
The molecule size of the polymer is especially significant since a molecule that is too large may not allow a little clay particle to fit correctly, or vice versa with a small molecule and a large sand particle.
While polymers are versatile soil stabilizers, not all of them are suitable for fine soils. Polymer’s lifespan and properties might differ based on the polymer. Traditional treatments, on the other hand, endure 1 to 3 years with minimum maintenance.
Most polymer applications create an impermeable surface that is impervious for the duration of the application. However, just as the lifespan varies, so may the performance of water.
Geotextiles are materials that are applied to soil to improve soil stability, reduce erosion, and aid in drainage. Geotextiles are available in a variety of sizes and thicknesses.
Some are woven, while others are thick plastic extrusions up to four inches thick. Geotextiles are mostly used to prevent erosion. They protect the top layer of soil from being moved by rain or water in this example.
Geotextiles can be used for road construction in particular places and purposes. Thicker extrusion geotextiles are frequently required for road building to give the necessary strength.
Geotextiles are available in a range of forms and sizes and can be applied to practically any soil type. Geotextiles are extensively used for erosion control.
Due to their high cost, they are rarely used for road building or big, heavy load applications. Geotextiles are typically labor-intensive due to their mechanical nature, as laborers must manually lay them out.