Building contractors have to meet a number of standard requirements before they begin any construction project. One of the most important requirements is soil stabilization. This article goes over everything you need to know about soil stabilization and the benefits associated with it.
What is Soil Stabilization?
Soil Stabilization is a process that transforms the physical properties of soil such that it is fit to provide long-term and permanent strength that withstands whatever structure is built on it. The process is achieved by increasing the overall bearing capacity and shear strength of the soil. In many cases, soil compaction may be a valuable approach to stabilizing soil. Once the soil has been successfully stabilized, a monolith is formed and this decreases soil permeability, reduces the soil’s shrink or swell potential, and eliminates the harmful effects of environmental elements, including the freeze and thaw cycle on the soil.
The shrink and swell potential of the soil is similar to contraction and expansion in liquids and metals. It refers to the ability of the soil to expand or contract in response to environmental factors like moisture. Through stabilization, you can easily eliminate the pores within the soil thus eliminating pockets where moisture may be stored. Eliminating the soil’s expansive feature can prevent safety issues in future, especially as some soils are capable of expanding as much as 10% of their original volume.
Soil stabilization can also improve in-situ or the natural state of the soil thus eliminating the costs associated with such future occurrences.
Soil Stabilization Methods
Unstable soils can be fixed in different ways, depending on what has been determined to be the best approach to its stabilization. Common methods of stabilizing soil include;
Chemical stabilization involves the addition of secondary material to the soil with the aim to change its natural state, performance, density, and its weight-carrying ability. The concentration of the chemical included in the soil-chemical mix will depend on the soil’s natural state and properties, the extent of landmass, and the chemical material added on. Common materials used for chemical soil stabilization include cement, fly ash and lime.
Common chemicals used for soil stabilization:
Calcium Chloride – Calcium Chloride is commonly used by contractors to stabilize the sub-base and base course during road construction. This is done to improve the stability of the soil underneath the asphalt for longevity and durability.
Sodium Silicate – Sodium Silicate is mainly mixed with water and calcium chloride and injected into fine and medium sands for stability. The hardening effect of the chemical improves the soil strength and compaction.
Cement – Cement is the oldest soil binding agent and is primarily used in all settings. The cement is mixed with water and layered over the soil or mixed with soil and water. The hardening effect prevents moisture percolation, eliminates air and soil pores, and increases compaction.
Lime – Lime is mainly used in black cotton soil due to the soil’s high instability. For the best outcomes, quicklime is mixed with the soil where it takes up water and solidifies.
Mechanical stabilization is one of the commonest solutions for stabilizing unstable soils. This involves the application of external force to reinforce and readjust the compactness and stability of the soil. The end goal is often achieved through heavy machinery like rollers, rammers, tempers, and pounding machines. Mechanical stabilization often offers a greater level of stability and solidity to soils and increases their compactness while forcing out pockets within the soil.
Soil stabilization can also be done mechanically through the use of geo-technology. Geotechnology involves the use of flexible and rigid materials placed within the layers of the soil to provide support and prevent expansion. For the best results, the three main geo-materials used for soil stabilization include;
Geotextiles – These are the thinnest and most flexible materials that can be layered between the soil to provide stability and hold the top layer from shifting or sinking.
Geogrids – They are similar to geotextiles but are bigger and wider. They retain flexibility and thinness and are used for their support structure to prevent soil shifts. Geogrids hold the soil in place and can be stacked, one atop another, for the best reinforcement results.
Geocells – These are the most rigid types of geomaterial used for soil stabilization. They are the most structurally supportive material of the three common geo-materials. Geocells have three-dimensional interlocking pockets designed to hold the soil or substrate in position from all of its sides. It offers tested and trusted protection against compaction, shifting, erosion, or other activities that can compromise the soil’s density.