Excavation and reuse
- Excavation length
- Excavation width
- Excavation depth
- Compacted fill required on site
Geotechnical · worked example · 4 pages
Earthworks quantities and haul planning
A basement excavation partly reused as site fill: the same soil occupies different volumes as bank (in the ground), loose (in the truck) and compacted (in the fill), and mixing them up is the classic quantity error. This sheet converts between the three states, then sizes the truck fleet and haul duration for the spoil.
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What this calculation covers
Material factors
- Bulking factor, bank to loose
- Shrinkage factor, bank to compacted
- Bank density of the soil
Cut, reuse and spoil (bank measure)
- Bank volume excavated
- Bank volume that makes the fill
- Bank volume of spoil to haul away
- Volume balance closes
- Spoil measured loose, in the truck
Truck trips
A trip carries whichever runs out first: the body's volume, or the volume the payload limit allows at this loose density. The effective load is the smaller of the two.
Here the 16 t payload would allow 10.5 m³, more than the 10 m³ body: volume governs. A denser soil or a smaller payload flips it.
- Truck body volume (loose)
- Truck payload limit
- Loose density of the spoil
- Volume the payload limit allows
- Effective load per trip — the smaller governs
- Mass of the governing load
- The governing load respects payload
- Truck trips, rounded up
- Total spoil mass hauled
Fleet and duration
- Round-trip cycle time per truck
- Trucks in the fleet
- Working day
- Working time to move the spoil
- Haul days, rounded up
Results summary
- The 900 m³ bank excavation reuses 389 m³ (bank) as the 350 m³ of compacted fill and leaves 511 m³ bank of spoil — 639 m³ loose, or 64 truck trips at 10 m³. Three trucks on a 40-minute cycle clear it in about 14 working hours: two days.
Try changing…
- Set the bulking factor to 1.4 (clay) — the same bank spoil becomes 716 m³ loose and 72 trips.
- Use 6 m³ trucks — trips rise to 107 and the haul stretches past three days.
- Need 500 m³ of fill — reuse takes 556 m³ bank and the spoil (and haul) shrinks by a third.