Last reviewed: July 13, 2026
Important: the spoil pile calculator models one free-standing cone only.
Windrows, flattened piles, merged piles, and multiple separated piles are not calculated by the tool. Treat those as field alternatives outside the model and run a separate site-layout check before using them for access, separation, or truck staging decisions.
How to Read These Examples
Each scenario below starts with a bank volume you can verify in the excavation calculator. That bank volume is then passed into the spoil pile calculator with a listed soil input and angle of repose so the loose volume, cone diameter, cone height, base area, and total staging area all come from the same calculator model.
The compact tables show the exact numbers to enter into /calculator/spoil-pile. If you use the same bank volume, soil type, and angle of repose, the calculator should reproduce the example exactly.
Scenario Walkthroughs
Example 1: Utility Trench Along a Property Line
A crew is digging a 24 m trench for water service. The average trench section is 0.9 m wide and 1.8 m deep. For the cone-model example below, use the calculator soil input Sand (Wet) and an angle of repose of 32 degrees.
| Step | Substitution | Result |
|---|---|---|
| Bank volume | 24 x 0.9 x 1.8 = 38.88 m3 | 38.88 m3 |
| Calculator soil input | Sand (Wet) | 20% swell |
| Loose volume | 38.88 x (1 + 20/100) | 46.66 m3 |
| Angle of repose input | Enter angle of repose = 32 degrees | 32 degrees |
| Cone diameter | Output from calculateSpoilPile | 8.3 m |
| Cone height | Output from calculateSpoilPile | 2.59 m |
| Base area | Output from calculateSpoilPile | 54.11 m2 |
| Total staging area | Base cone footprint plus 0.6096 m (2 ft) setback ring | 71.17 m2 |
Reproduce this one exactly by entering 38.88 for bank volume, selecting Sand (Wet), and entering 32 degrees in the spoil pile calculator.
If the round cone does not fit beside the property line, a long windrow parallel to the trench is a field alternative outside this model and needs a separate site-layout check.
Example 2: Small Foundation Dig Behind a House
A detached garage foundation needs a 9 m by 6 m excavation at 1.2 m deep. For the reproducible spoil example, use the calculator soil input Topsoil/Loam and an angle of repose of 35 degrees.
| Step | Substitution | Result |
|---|---|---|
| Bank volume | 9 x 6 x 1.2 = 64.8 m3 | 64.80 m3 |
| Calculator soil input | Topsoil/Loam | 25% swell |
| Loose volume | 64.80 x (1 + 25/100) | 81 m3 |
| Angle of repose input | Enter angle of repose = 35 degrees | 35 degrees |
| Cone diameter | Output from calculateSpoilPile | 9.6 m |
| Cone height | Output from calculateSpoilPile | 3.36 m |
| Base area | Output from calculateSpoilPile | 72.38 m2 |
| Total staging area | Base cone footprint plus 0.6096 m (2 ft) setback ring | 91.93 m2 |
Reproduce this one exactly by entering 64.8 for bank volume, selecting Topsoil/Loam, and entering 35 degrees in the spoil pile calculator.
If tree limbs or a driveway apron block the cone footprint, a flattened stockpile is a field alternative outside this model and still needs a separate fit check.
Example 3: Basement Excavation With Partial Reuse
A basement cut is 14 m by 10 m at an average depth of 2.6 m. For this single-pile calculator run, use the soil input Clay (Light/Sandy) and an angle of repose of 38 degrees.
| Step | Substitution | Result |
|---|---|---|
| Bank volume | 14 x 10 x 2.6 = 364 m3 | 364.00 m3 |
| Calculator soil input | Clay (Light/Sandy) | 30% swell |
| Loose volume | 364.00 x (1 + 30/100) | 473.2 m3 |
| Angle of repose input | Enter angle of repose = 38 degrees | 38 degrees |
| Cone diameter | Output from calculateSpoilPile | 16.66 m |
| Cone height | Output from calculateSpoilPile | 6.51 m |
| Base area | Output from calculateSpoilPile | 217.99 m2 |
| Total staging area | Base cone footprint plus 0.6096 m (2 ft) setback ring | 251.06 m2 |
Reproduce this one exactly by entering 364 for bank volume, selecting Clay (Light/Sandy), and entering 38 degrees in the spoil pile calculator.
If reusable fill must stay separate from unsuitable material, multiple separated piles are a field alternative outside this one-cone model and require a separate layout and sequencing plan.
Example 4: Cut-and-Fill Export Area With Truck Haul-Off
A site cut removes a surplus 18 m by 12 m area to an average depth of 1.5 m. For this example, use the soil input Clay (Heavy) and an angle of repose of 40 degrees so the spoil example matches a steep, cohesive temporary pile.
| Step | Substitution | Result |
|---|---|---|
| Bank volume | 18 x 12 x 1.5 = 324 m3 | 324.00 m3 |
| Calculator soil input | Clay (Heavy) | 35% swell |
| Loose volume | 324.00 x (1 + 35/100) | 437.4 m3 |
| Angle of repose input | Enter angle of repose = 40 degrees | 40 degrees |
| Cone diameter | Output from calculateSpoilPile | 15.86 m |
| Cone height | Output from calculateSpoilPile | 6.65 m |
| Base area | Output from calculateSpoilPile | 197.56 m2 |
| Total staging area | Base cone footprint plus 0.6096 m (2 ft) setback ring | 229.1 m2 |
Reproduce this one exactly by entering 324 for bank volume, selecting Clay (Heavy), and entering 40 degrees in the spoil pile calculator.
If truck cycling is intermittent, several smaller buffer piles can be more practical in the field, but merged piles or multiple staging pods are not calculated by the cone tool.
Methodology and Limitations
The workflow is fixed: compute bank volume, apply the selected swell factor to get loose volume, then let calculateSpoilPile solve a single cone from that loose volume and the chosen angle of repose. The cone model uses the pile radius to derive diameter, height, base area, and the total staging area that includes the OSHA 2 ft setback ring.
These examples are planning examples, not a full staging design. They do not calculate trench-edge loading, haul-road turning, pile flattening under equipment traffic, separated reusable-versus-unsuitable stockpiles, or multiple stockpiles distributed around the site. If your field plan needs any geometry other than one free-standing cone, use these numbers only as a starting point and verify the alternate layout separately.
Practical Workflow for Your Own Job
Start with the excavation calculator for the in-place quantity, move that bank volume into the spoil pile calculator, and use the same soil label and angle-of-repose assumptions you expect in the field. If the resulting cone footprint does not fit, that does not mean the volume is wrong. It means the alternate layout needs its own site check because the calculator is only solving one cone.