What does soil "creep" refer to?

Soil "creep" refers to the slow, continuous deformation or movement of soil under sustained load, making it a critical concept in geotechnical engineering and construction. This phenomenon occurs due to the gradual reorientation of soil particles and can be influenced by factors such as gravity, moisture changes, and the weight of structures or overlying materials.

Understanding soil creep is essential for engineers and builders, as it can affect the stability of structures, roadways, and slopes over time. This slow movement can lead to issues like foundation settlement or landslides if not properly accounted for in design and construction practices.

In contrast, the other choices describe different soil behaviors. The rapid movement of soil during an earthquake refers to landslides or liquefaction, while seasonal expansion and contraction are related to soil shrink-swell behavior often caused by moisture changes. Lastly, the layering of soil over time aligns more with sedimentation processes rather than the gradual movement associated with creep.