Construction Engineering
Swell and Shrinkage
The change in volume of soil between its natural (bank), excavated (loose) and compacted states.
Soil excavated from the ground bulks up: loose volume = bank volume × (1 + swell). Compacted into a fill, it ends up denser than in the bank: compacted volume = bank volume × (1 − shrinkage). Common earth swells by roughly 20% to 30%.
Hauling is counted in loose cubic yards, because that is what fills a truck, while excavation is usually paid in bank cubic yards and embankment in compacted yards. Mixing the three states is the commonest error in earthwork estimates.