Why is Clay Soil Used if it Has a High Shrinking and Compaction Capacity?

Clay soil is commonly used as both a foundation and a filler soil. It has the highest swell-shrink capacity of any soil, which means settling is to be expected. So why is it still used in construction if it causes settling? Well, just as there are a few downsides to using clay soils, there are upsides as well. 

• Easy Compaction  

It’s important for soil to be well compacted if it’s going to be placed down as a foundation. The more compacted soil is, the better it is as a foundation. Water does not flow through dense soil very easily, so compaction prevents erosion as well as excessive shifting in the soil. 

Clay soils are very difficult to break apart due to how well they hold together once pressed. This is very important, and site managers would rather have soil that doesn’t shift easily over soil that doesn’t hold well, even if settling is more frequent in the former. 

• Fast Results  

Because clay compacts so well, it’s very easy to lay down as a foundation. When compacting, contractors have to make sure they are thorough. Poorly compacted soil causes many problems and can destroy a structure’s integrity. However, if a soil that isn’t easily compacted is used, it takes a lot longer to lay down. 

Clay soils are easy to manipulate. It doesn’t take long to thoroughly compact, so it can be laid down a lot faster than other soils. Well-compacted soil and fast results are a lot more important than little shrinkage capacities for some site managers. This is why clay soils are still used as a foundation, despite the higher rates of settling with this kind of foundation material.