Calculator Input
Example Data Table
| Case | Hole Diameter | Inner Diameter | Depth | Yield/Bag | Waste + Safety | Adjusted Volume |
|---|---|---|---|---|---|---|
| Micropile Casing | 12 in | 8 in | 120 ft | 1.15 ft³ | 15% | 56.81 ft³ |
| Borehole Seal | 250 mm | 168 mm | 36 m | 0.032 m³ | 18% | 1.24 m³ |
| Driven Pile Sleeve | 18 in | 14 in | 40 ft | 1.10 ft³ | 12% | 17.60 ft³ |
Formula Used
Annulus area = π ÷ 4 × (Hole Diameter² − Inner Diameter²)
Theoretical volume = Annulus area × Grouted depth × Number of sections
Adjusted volume = Theoretical volume × (1 + Waste %) × (1 + Safety %)
Exact bags = Adjusted volume ÷ Yield per bag
Rounded bags = Ceiling of exact bags
Total water = Rounded bags × Water per bag
Material cost = Rounded bags × Cost per bag
Use consistent field units. The calculator converts metric entries internally before returning results in the selected system.
How to Use This Calculator
- Select imperial or metric units.
- Enter the outer bore diameter and the inner member diameter.
- Input the grout depth or length to be filled.
- Add grout yield, water demand, bag cost, and bag weight.
- Include waste and safety percentages for field conditions.
- Set the number of identical sections when repeating the same detail.
- Press the calculate button to show results above the form.
- Export the result summary as CSV or PDF for site records.
Frequently Asked Questions
1. What is annulus grout quantity?
It is the grout volume needed to fill the ring-shaped space between a borehole wall and an inner casing, pile, pipe, or sleeve.
2. Why does the calculator ask for waste and safety factors?
Field losses, overbreak, leakage, and setup uncertainties can increase actual consumption. These factors help convert theoretical geometry into a more practical procurement quantity.
3. Should I use inside or outside casing diameter?
Use the outside diameter of the inner element because the grout surrounds the exterior surface. Inside diameter would understate the filled annular space.
4. What does yield per bag mean?
Yield per bag is the mixed grout volume produced by one bag under your mix design. Manufacturer data sheets often provide this value.
5. Why are exact bags and rounded bags both shown?
Exact bags show the raw calculation. Rounded bags show the whole bags you must purchase, transport, and stage in the field.
6. Can I use this for borehole sealing and micropiles?
Yes. It suits drilled shafts, micropiles, borehole seals, sleeves, anchor holes, and similar annular fills when the section is circular.
7. Does the calculator include grout pressure or pump rate?
No. It focuses on quantity, water demand, and material cost. Pump pressure and placement rate depend on mix rheology and site methods.
8. What if the borehole is not perfectly circular?
Use a conservative diameter or increase the waste allowance. Irregular profiles and overcut conditions usually require extra grout beyond geometric volume.