Soil Swell / Shrinkage Volume Conversion
Convert bank cubic yards to loose (truck) and compacted (placed) volume.
Example
You enter
- Bank (in-place) volume (cy) 100
- Swell when excavated (%) 25
- Shrinkage when compacted (%) 15
You get
- Loose (truck / stockpile) volume 125 cy
- Load factor (bank per loose) 0.8
- Compacted (placed) volume 85 cy
Details, formula, and sources
Convert bank (in-place) cubic yards to loose (truck) and compacted (placed) volume with the load factor and the borrow shortfall. The geotech report governs the percentages.
loose = bank x (1 + swell/100); load_factor = 1/(1 + swell/100); compacted = bank x (1 - shrink/100); fill_shortage = bank - compacted.
Caterpillar Performance Handbook soil-conversion method (swell / shrinkage / load factor) by name; first-principles volume conversion.
The swell / shrinkage / load-factor concept is published earthmoving practice. The percentages come from the geotech report or a published soil table.
Estimate. AHJ and licensed professional govern.
Field names used by the API: bank_cy, swell_pct, shrink_pct, loose_cy, load_factor, compacted_cy
- Soil percentages swell (sand ~12, common earth ~25, clay ~30, rock ~50+) and shrinkage (~10-20) from the geotech reportCaterpillar Performance Handbook / geotech