Calculation Results
Required estimates based on your parameters:
Undisturbed Bank Volume
333.33 yd³
Natural ground state cavity
Loose Haul-Off Volume
433.33 yd³
Requires 44 truck runs
Compacted Backfill Volume
283.33 yd³
Final compacted state density
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An excavation calculator is a geotechnical material takeoff estimator that calculates undisturbed bank volume, loose swell volume, and compacted backfill volumes. Working under standard design methodologies, it scales cavity dimensions to output exact dump truck haul-off requirements.
How to Calculate Excavation Volumes & Haulages
Earthwork sizing requires finding the undisturbed bank volume of an excavation and applying material swell/shrink ratios. Swell and load factors conform to the Caterpillar Performance Handbook standards [1], USBR Earth Manual specifications [2], and ASTM D698 compaction testing codes [3]. Correct earthwork planning prevents transport overload by checking soil swell factors and calculating the compaction weight. Check our Concrete Volume Calculator when filling excavated footings.
Excavation Sizing Formulas
- US Bank Volume (cu yd): BCY = (Length (ft) × Width (ft) × Depth (ft)) ÷ 27
- Loose Volume (cu yd): LCY = BCY × (1 + Swell Factor ÷ 100)
- Compacted Volume (cu yd): CCY = BCY × (1 - Shrink Factor ÷ 100)
- Dump Truck Loads Count: Runs = ⌈ Loose Volume ÷ Truck Capacity ⌉
- Metric Bank Volume (m³): m³ = Length (m) × Width (m) × Depth (m)
Step-by-Step Worked Examples
Example 1 — US Standard (Imperial):
Suppose a commercial foundation cavity measures **50 ft long by 30 ft wide by 6 ft deep**. The soil is clay (swell factor = 30%, shrink factor = 15%) and the haul trucks carry 10 cubic yards.
1. Calculate bank volume in cubic feet: 50 × 30 × 6 = 9,000 cu ft
2. Convert to cubic yards (BCY): 9,000 ÷ 27 = 333.33 BCY
3. Compute loose volume (LCY): 333.33 × 1.30 = 433.33 LCY
4. Compute compacted volume (CCY): 333.33 × (1 - 0.15) = 283.33 CCY
5. Calculate truck runs needed: ⌈ 433.33 ÷ 10 ⌉ = ⌈ 43.33 ⌉ = 44 runs
Suppose a commercial foundation cavity measures **50 ft long by 30 ft wide by 6 ft deep**. The soil is clay (swell factor = 30%, shrink factor = 15%) and the haul trucks carry 10 cubic yards.
1. Calculate bank volume in cubic feet: 50 × 30 × 6 = 9,000 cu ft
2. Convert to cubic yards (BCY): 9,000 ÷ 27 = 333.33 BCY
3. Compute loose volume (LCY): 333.33 × 1.30 = 433.33 LCY
4. Compute compacted volume (CCY): 333.33 × (1 - 0.15) = 283.33 CCY
5. Calculate truck runs needed: ⌈ 433.33 ÷ 10 ⌉ = ⌈ 43.33 ⌉ = 44 runs
Example 2 — GCC/Metric Standard:
Suppose a foundation excavation measures **15 m long by 9 m wide by 2 m deep**. The soil is clay (swell factor = 30%, shrink factor = 15%) and the dump trucks carry 8 cubic meters.
1. Calculate bank volume in cubic meters: 15 × 9 × 2 = 270.0 m³
2. Compute loose volume: 270 × 1.30 = 351.0 m³
3. Compute compacted volume: 270 × (1 - 0.15) = 229.5 m³
4. Calculate truck runs needed: ⌈ 351.0 ÷ 8.0 ⌉ = ⌈ 43.88 ⌉ = 44 runs
Suppose a foundation excavation measures **15 m long by 9 m wide by 2 m deep**. The soil is clay (swell factor = 30%, shrink factor = 15%) and the dump trucks carry 8 cubic meters.
1. Calculate bank volume in cubic meters: 15 × 9 × 2 = 270.0 m³
2. Compute loose volume: 270 × 1.30 = 351.0 m³
3. Compute compacted volume: 270 × (1 - 0.15) = 229.5 m³
4. Calculate truck runs needed: ⌈ 351.0 ÷ 8.0 ⌉ = ⌈ 43.88 ⌉ = 44 runs
Common Mistakes & Pro Tips
- Ordering Gravel by Loose Volumes: Gravel suppliers deliver material by loose volume, but your prints design compacted thicknesses. Compressing base aggregate reduces volume by about 10-15%. Check target compaction shrink values before placing material orders.
- Forgetting the Excavation Angle: Excavations deeper than 4-5 feet require sloping or shoring under OSHA safety codes to prevent cave-ins. Simple rectangular math underestimates excavation volumes because it assumes vertical vertical sidewalls instead of stepped or sloped layouts.
- Ignoring Water Content Swell: Wet, saturated soils swell up to 10% more than dry soils, and carry significantly higher weights. Adjust load limits on utility trailers to prevent highway violations.
Soil Material Earthwork Factors
| Soil Material Class | Swell Factor (%) | Shrink Factor (%) | Bank Density (US) | Standard Compaction Limit |
|---|---|---|---|---|
| Clay Soil | 30% | 15% | 2,700 lb/yd³ | 95% Modified Proctor |
| Sand & Clean Gravel | 10% | 5% | 3,000 lb/yd³ | 98% Standard Proctor |
| Loam / Topsoil | 20% | 10% | 2,400 lb/yd³ | 85% Landscaping Density |
| Blasted Rock | 50% | -10% (Expands) | 4,200 lb/yd³ | Non-shrink fill course |
Related Estimating Resources:
Frequently Asked Questions (FAQ)
Sources & References
- Caterpillar Handbook: Earthwork volume swell factors. Source Link
- USBR Earth Manual: Geotechnical engineering backfill standards. Source Link
- ASTM D698: Standard laboratory compaction test procedures. Source Link
- ISO 22476: Geotechnical site testing standards. Source Link
- AWWA M45: Structural soil stiffness evaluations. Source Link
- SBC 303: Saudi Building Code geotechnical standards. Source Link
- WSDOT Earthwork: Road subgrade compaction guidelines. Source Link
- AASHTO T 99: Moisture-density soil curve relationships. Source Link
- BS 1377: British standards for testing soils. Source Link
- SAES-A-114: Saudi Aramco structural soil backfill codes. Source Link