Site investigation · Geophysics & monitoring
Blast vibration: site law regression and charge limits calculator
Regresses monitored peak particle velocities against scaled distance to find the site constants, then the maximum charge per delay that keeps a structure within its limit.
Standard: PPV = K(D/√W)^(−B) · AS 2187.2-2006 Appendix J guide limits
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Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Distance to the structure | 120 | m |
| Proposed charge per delay | 20 | kg |
| Limit | 10 mm/s houses / low-rise residential | mm/s |
| Records: distance (m), charge per delay (kg), PPV (mm/s) | 30, 5, 16.20 45, 10, 16.61 60, 8, 7.69 80, 20, 10.58 100, 15, 6.29 120, 25, 7.49 150, 30, 6.28 200, 40, 4.55 250, 30, 2.32 300, 50, 2.82 |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Site exponent B = −slope | 1.57 | |
| Site constant K = 10^intercept | 1,031 | |
| Fit R² | 0.989 | |
| Design scaled distance D/√W | 26.83 | m/kg^½ |
| Predicted PPV | 5.81 | mm/s |
| Scaled distance for the limit | 19.00 | m/kg^½ |
| Maximum charge per delay (D/SD)² | 39.89 | kg |
- ✓ Predicted PPV ≤ limit
- ✓ Regression R² ≥ 0.7
Method, formulas and assumptions
- Site exponent B = −slope = -SLOPE([t.ly],[t.lx]) = 1.5743
- Site constant K = 10^intercept = 10^INTERCEPT([t.ly],[t.lx]) = 1030.5
- Fit R² = RSQ([t.ly],[t.lx]) = 0.98916
- Design scaled distance D/√W = 120/SQRT(20) = 26.833 m/kg^½
- Predicted PPV = 1030.5*26.833^(-1.5743) = 5.8074 mm/s
- Scaled distance for the limit = (10/1030.5)^(-1/1.5743) = 18.999 m/kg^½
- Maximum charge per delay (D/SD)² = (120/18.999)^2 = 39.891 kg
- A mean-line law is exceeded by about half of blasts; for compliance use an upper-bound (e.g. 95 %) line from the regression scatter. Airblast limits (AS 2187.2) are checked separately.
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.