Trench Excavation Calculator
Determine trench cut volume, soil swell expansion, loose haul-off volume, and dump truck counts.
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Tested hardware and components for high reliability
Bank Cubic Yards vs. Loose Cubic Yards
In earthmoving, undisturbed in-ground soil is termed Bank Cubic Yards (BCY). When excavated, the compacted soil particles separate, introducing air pockets that cause the soil volume to expand ("swell") into Loose Cubic Yards (LCY):
In-situ Volume (BCY) = (Length ft × (Width inches / 12) × Depth ft) / 27
Haul-Off Volume (LCY) = BCY × Swell Factor
Failing to account for swell results in running out of dump trucks, because a 30 BCY trench generates 38 to 45 yards of loose dirt to haul away.
Frequently Asked Questions
What is a typical swell percentage for clay or topsoil?
Common loam soil swells by 20% to 25%, dense virgin clay swells by 30% to 35%, and solid rock swells by 50% to 65% when blasted or chipped.
How many cubic yards does a standard tandem dump truck carry?
A standard tandem dump truck carries 10 to 12 loose cubic yards, while a tri-axle truck can carry 14 to 16 loose yards.
How much bedding gravel is needed under utility pipe?
Plumbing and utility codes typically mandate a 4" to 6" bed of washed #57 crushed stone or sand under the pipe, with another 6" to 12" covering the crown before backfilling with native soil.