What does "shrinkage" refer to in earthwork?

Shrinkage in earthwork specifically refers to the decrease in volume that occurs when soil transitions from its natural state, which is typically loose and uncompact, to a compacted state. This is an important concept in civil engineering and construction because it affects the calculations for earth materials used in projects, such as embankments, excavations, and backfill.

When soil is compacted, air and water are expelled from the voids between soil particles, leading to a denser arrangement of the soil. This compaction results in a reduction of volume and is crucial for ensuring stability and strength in construction applications. Understanding shrinkage helps engineers estimate how much soil will be needed for projects and how much will settle after placement.

The focus on volume change during compaction reflects the physical behavior of soils when subjected to mechanical forces, which is a fundamental aspect of geotechnical engineering practices. Hence, this concept is essential for accurately predicting the behavior and characteristics of soil in various civil engineering applications.