Clay Shrinkage Explained

Clay shrinkage subsidence or clay soil subsidence refers to the occurrence of ground sinking or settling, due to the shrinking and compacting of clay-rich soils. This type of subsidence commonly occurs in areas with expansive clay-rich soils which can be impacted by changes in moisture content Seasonal changes are also known to be a common cause of clay shrinkage subsidence, with moisture from the ground often being extracted by tree roots during the warm summer months.

During autumn and winter months, the returning moisture can cause the foundations of a building to move upwards, and the repetition of this process, caused by seasonal changes throughout the year can make the subsidence significantly worse. The longer that this process goes on without being addressed, the worse it will get, making repairs more difficult, and significantly more costly.

This makes early detection and repairs very important when it comes to clay shrinkage subsidence. Our experts at RIT are able to do this by carrying out a soil investigation.

The Soil Investigation Process

A soil investigation by one of our experts is a simple process that will reveal a lot when I comes to clay shrinkage subsidence. By analysis the soil, we can detect the depth of the deepest tree roots to address the problem. This process is important before any work is carried out, and it will involve:

• Determining the depth, thickness and foundation type.

• Construction of a borehole either 3 or 5 metres below ground level. This will tell our engineers about the strength of the clay, its moisture content, and the likelihood of it shrinking. This step will also help in identifying the depths of the deepest roots below the foundations.

• Analysis of soil composition for obstacles.

Resin Injection Solution for Clay Shrinkage Subsidence

The process used at RIT involves injecting the ground with expanding resins at a depth of at least 0.5 metres below the deepest tree or plant roots. Resin will then be injected at different levels until reaching the underside of the foundations. The resin will then flow and fill into all cracks and voids, preventing any moisture from getting in and being extracted by clay during the seasonal changes throughout the year. This methods avoids the need for a costly excavation, whilst significantly reducing the shrinking and swelling caused by the changes in moisture.

The savings provided by the use of our Resin Injection are substantial. As well as this, we also provide a much faster alternative to piling and underpinning. The scale of the job becomes greatly reduced when customers use Resin Injection with RIT. This allows for customers to benefit from the fact that normal work can continue on site due to the method of application we use. This method includes the injection of expanding resins into the foundation soils, and is a far more cost efficient, and disruptive method of ground improvement.

Why Use Resin Injection for Clay Shrinkage Subsidence?

Older methods of soil and ground stabilisation such as underpinning are far more intrusive and cumbersome approaches. Underpinning is often costly, time consuming and disruptive. The scale of the project when underpinning is used is far greater, the huge amounts of concrete are expensive and the excavation work is labour intensive. Resin injection with RIT offers a far more convenient approach.