Swelling/Shrinkage Factor

Definition

The swelling factor refers to the increase in volume of soil when excavated and stockpiled due to air voids. The shrinkage factor is the percentage of loose soil volume that remains after compaction.

Purpose

The purpose of understanding the swelling and shrinkage factors is to accurately estimate the volume changes of soil during excavation and compaction processes, crucial for earthmoving and construction planning.

Examples of Use

• Road construction projects calculate swelling and shrinkage factors to determine the amount of fill material needed.
• Land development plans use these factors to estimate the volumes of cut and fill required for grading.
• Pipeline installations consider swelling and shrinkage to ensure proper trench backfilling and soil stability.

Related Terms

• Compaction: The process of reducing soil volume by applying pressure.
• Loose Volume: The expanded volume of soil after excavation.
• Bank Volume: The original, undisturbed volume of soil before excavation.

Notes

Accurate calculations of swelling and shrinkage factors are essential for efficient material management and avoiding project delays due to incorrect volume estimates.