The Three Main Types of Soil Stabilisation

by | Jun 11, 2021

It’s true that the technique of soil stabilisation (or soil mixing) has been applied in building and construction for thousands of years. Both the Mesopotamian and Roman empires pioneered the technique of stabilising terrain with the intention to ferry men, wagons and materials through tough and demanding environments. 

In the earliest examples of this now-ancient process, the soil which supported the pathways used by these ancient civilisations was modified by way of compounding the earth with stabilising agents such as calcium and pulverised limestone. This method was so effective that there are sections of the UK’s roadway system that were built by the Romans using this very technique that still stand today.  

It should come as no surprise that, after 2000 odd years, there have been some significant developments in the act of soil stabilisation. However, whilst some methods and procedures may have changed throughout the years, the core reason for doing so remains the same. That is to improve the strength, durability or bearing capacity of a surface area. 

The three main types of soil stabilisation are biological, physical and chemical, each of which Borehole Solutions have an extensive understanding of and the processes which go in to employing them. Below we have outlined the differences of all three, detailing how they are achieved, why they may be used and how the outcome of each may vary depending on the project they are intended for.  

Biological Soil Stabilisation 

Primarily, biological soil stabilisation is a method used to improve the stability of soil which is expected to be heavily affected by weather. The technique involves the planting of trees and tree seedlings within a previously barren area. Whilst the introduction of forestation is generally an organic and natural process, the initial sowing of seedlings should be accompanied by others forms of stabilisation to assist in the early stages of a plant’s growth. If not, factors such as wind, rain and excessive weather conditions may hinder or completely kill the seeds or young plants development. The advantages of utilising such biological methods for land and soil enhancement has proven to greatly assist geotechnical engineering applications in regard to both performance and environmental maintainability.  

Chemical Soil Stabilisation 

Whilst the use of chemicals is present in most forms of soil stabilisation, some techniques rely more heavily on chemical use than others. Chemical soil stabilisation occurs when chemical additives – such as lime and cement – are added to increase the stability, swell reduction and overall resistance of an area by way of modification of soil particles. This is achieved following a chemical reaction which transforms the treated area after the addition of water. However, the actual efficiency of the stabilisation can differ depending on the reaction between the agent and the soil particle makeup. Because the outcome of this process largely depends on this factor, it is important to use the correct stabiliser with a particular soil type. 

Physical Soil Stabilisation  

Physical/mechanical soil stabilisation incorporates the use of soils of different grades in order to increase solidity and gradation. In turn, the process adjusts the natural characteristics of soil by way of altering its natural particle size. There are five techniques within this (rather broad) field that can be adopted to treat soil in this way. They are called; Compaction, Pre-Wetting, Soil Reinforcement, Wetting Dry Cycle and Solid Waste. 

Compaction 

One of the more widely used methods within soil stabilisation is compaction. This procedure uses mechanical plant and machinery as a way to extract air voids from soil density to further increase the load bearing capabilities of the treated area.  

Pre-wetting 

Pre-wetting is a historic form of soil stabilisation in which an area is purposely saturated to create an environment which makes any further absorption of water to the area more manageable due to the already high moisture volume created by the process, originally. 

Soil Reinforcement 

Soil reinforcement is the method of reinforcing weak soils by way of using fibrous materials of either an organic or synthetic nature, subsequently, resulting in an increased density of the soil to improve both sustainability and stability.  

Wetting Dry Cycle 

The Wetting Dry Cycle is the act of soaking an area with water and allowing for the soil to then dry. This method is repeated in a series of cycles, hence the name, until the desired solidity is achieved. 

Solid Waste 

Solid waste stabilisation involves utilising such waste products as plastic, glass, wood and rubber along with other more organic materials with a binding agent such as cement or asphalt to form a solid block or base for building.  

Contact Us 

The Borehole Solutions team are available to discuss how we can assist with any questions regarding the matter of soil stabilisation or any of the services we have to offer either via phone on 01733 200 501 or alternatively by emailing us at info@boreholesolutions.com. There is also the option to contact us via social media.