Earthwork Swell & Shrink Calculator

How the earthwork swell & shrink calculator works

Both volume changes refer to the original bank volume. Loose volume = bank volume × (1 + loose increase / 100). Compacted volume = bank volume × (1 − compacted reduction / 100). The compacted reduction must be below 100%; it is not a reduction from loose volume.

Conserved dry mass = bank volume × entered bank dry density. Implied loose and compacted dry densities divide that mass by the respective calculated volumes. At zero bank volume, mass and volumes are zero and the density ratios are unavailable.

This scenario assumes no imported material, removed fines, water mass change or loss. Factors depend on actual material and conditions. The results do not prescribe target density, compaction effort, test acceptance, safe slopes or hauling limits. Caterpillar discusses bank/loose conventions; these explicit forward factors avoid relying on ambiguous inverse load-factor terminology.

Worked example

100 m³ bank volume with 25% loose increase becomes 125 m³ loose. A separate 10% reduction from bank gives 90 m³ compacted. At 1.8 tonnes/m³ bank dry density, conserved mass is 180 tonnes. Implied loose density is 1.44 tonnes/m³ and compacted density is 2. Changing loose increase to 50% gives 150 m³ loose and 1.2 tonnes/m³ implied loose density.

Sources and assumptions

The source material explains the underlying calculation or pricing structure. Entered prices, costs, schedules and scenario choices are your assumptions; this tool does not obtain supplier quotes or predict actual results.

• Caterpillar: bank, loose and material volume factors