In soil mechanics, what does the term "consolidation" refer to?

The term "consolidation" in soil mechanics specifically refers to the process of soil compacting under load over time. When soil is subjected to an external load, such as the weight of buildings or other structures, the soil particles rearrange and the water within the pore spaces is expelled. This leads to a decrease in volume, resulting in an increase in the soil's density and strength. The consolidation process is significant in assessing how soil behaves under different loading conditions, particularly in terms of settlement, stability, and material performance. This phenomenon occurs gradually as the saturated soil takes time to expel water and adjust to the new load, underscoring the importance of understanding consolidation in geotechnical engineering.

Other options do not correctly describe consolidation. Moisture retention pertains to how soil holds water, while chemical breakdown concerns the interactions between soil components, and freezing references the physical effects of temperature on water present in soil pores, none of which directly relate to the load-related volume change referred to by consolidation.