What happens to soil volume when it swells after excavation?

When soil swells after excavation, the volume of the soil typically increases. This phenomenon occurs due to several factors, including the moisture content of the soil and its mineral composition. When soil is excavated, it often experiences a change in its moisture balance, which can cause clay particles to absorb water and expand. This expansion may be attributed to the soil structure, where tiny particles may rearrange themselves to create more space when they become wet or when they are disturbed.

Additionally, the process of excavation can also lead to the breaking apart of soil aggregates, which may allow for more air to fill the spaces between soil particles, further contributing to an increase in overall volume. It's important to consider that this swelling behavior is typically more pronounced in specific soil types, such as clayey soils, where the attraction of water molecules to the clay particles causes significant volumetric changes.

The other choices don’t accurately reflect the behavior of soil after excavation. For instance, suggesting that the soil volume decreases would overlook the physical processes of expansion that occur in many types of soil. Saying it stays the same would not account for the changes occurring when soil is disturbed and can no longer maintain its original structure. Lastly, the notion that it solidifies does not align with the typical reaction