Site investigation · Laboratory: soil classification
Liquid limit: Casagrande cup calculator
Flow curve (w against log N) by least squares; LL at 25 blows and the flow index.
Standard: AS 1289.3.1.1 · ASTM D4318
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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 |
|---|---|---|
| Points: blows N, moisture (%) | 34, 47.2 27, 49.0 21, 50.9 16, 52.8 |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Slope dw/dlogN | -17.12 | % |
| Intercept | 73.47 | % |
| Liquid limit at 25 blows | 49.54 | % |
| Flow index (per log cycle) | 17.12 | % |
- ✓ Blows bracket 25 (15–35)
Method, formulas and assumptions
- Slope dw/dlogN = SLOPE([t.w],[t.lg]) = -17.121 %
- Intercept = INTERCEPT([t.w],[t.lg]) = 73.47 %
- Liquid limit at 25 blows = 73.47+-17.121*LOG10(25) = 49.536 %
- Flow index (per log cycle) = --17.121 = 17.121 %
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.