The importance of soil compaction testing

Soil compaction testing is a way to measure how much a quantity of soil can be compressed into a smaller space.

Compaction is a natural process in which the solid part of soil settles into the air spaces in between, but it depends on several factors, such as the forces exerted on the soil.

Over time, soil compaction leads to a denser material – you can see this easily when you water a freshly potted plant and the soil level in the pot drops significantly.

Because of the changes in volume, strength and permeability, soil compaction testing is an important process that should not be neglected during any engineering or construction work.

 

What are the risks of soil compaction?

Loose soil can compact significantly, especially when placed under substantial pressure from above, or after becoming waterlogged and then drying out.

This can cause the level of the land to drop, leading to subsidence and other issues. This is not only a risk to buildings, but can also lead to other surfaces becoming uneven, such as driveways, pavements and car parks.

In the immediate term, there is also a risk to vehicles and machinery attempting to move over loose soil during construction work, and potentially sinking into the ground as it compacts.

 

What are the benefits of soil compaction?

Compacted soil is more solid and less porous. This can have benefits in many applications, making a firmer surface to build on and reducing the risk of subsidence in the future.

For large engineering works, compacted soil allows firm foundations, especially on very large structures like dams, bridges and man-made embankments.

However, very compacted soil can have implications for drainage as it is less porous, as well as aesthetic landscaping like lawns, flowerbeds and shrubberies, as plants may find it more difficult to put down roots.

 

How to test soil compaction

There is complex science behind soil compaction, as there’s a ‘goldilocks’ level of water content that maximises the compressibility of the earth – enough to lubricate the dry particles, but not enough to resist them packing together.

Soil compaction testing typically involves taking a sample of earth and adding water to it, then measuring the weight of soil that can be compacted into a fixed volume at that level of moisture content.

The process is repeated several times with different amounts of water, and the results plotted to find the optimum moisture level for the soil.

If you would like to know more or you have a site where you need soil compaction testing to be carried out, contact hebs Group today on 0151 2360707 and we will be happy to help.

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