What does the term "settlement" refer to in soil engineering?

In soil engineering, the term "settlement" specifically refers to the vertical downward movement of ground due to soil consolidation. This process occurs when soil particles rearrange and compact under the weight of structures, leading to a decrease in volume. As load is applied to the soil, pore water is expelled, and the soil consolidates, resulting in settlement. This phenomenon is particularly important in the context of construction and foundation design, as it can affect the stability and integrity of structures built on the soil.

Understanding settlement is crucial for engineers because excessive settlement can lead to structural issues, including cracking or shifting of buildings, roads, and other infrastructure. By properly accounting for and mitigating settlement during the design and construction phases, engineers can ensure safe and effective construction practices.

The other options, while related to soil behavior, do not accurately capture the definition of settlement in soil engineering. Compaction refers more to the process of increasing soil density, moisture content pertains to the water present in the soil, and natural elevation due to vegetation growth does not relate to the term settlement in the context of soil engineering practices.