Site investigation · In-situ testing
Borehole log builder calculator
Draws a borehole log from a layer table (base depth, soil type code, SPT N, description) with groundwater, and summarises layer thicknesses, depth to weathered rock and N values.
Standard: AS 1726-2017 soil description · SPT N profile · groundwater
Open the live calculator → All site investigation calculators
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 |
|---|---|---|
| Ground level (RL) | 4.5 | m AHD |
| Groundwater depth | 1.8 | m |
| Layers: base depth (m), type 1 Fill 2 Clay 3 Silt 4 Sand 5 Gravel 6 Organic 7 Weathered rock 8 Rock, SPT N, description | 0.8, 1, 6, Sandy FILL 3.5, 4, 8, Loose SAND 6.0, 2, 4, Soft CLAY 9.5, 4, 28, Medium dense SAND 12.0, 7, 50, Extremely weathered SANDSTONE 14.0, 8, 100, Sandstone |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Total depth | 14.00 | m |
| Lowest N | 4.00 | |
| Groundwater RL | 2.70 | m AHD |
| Depth to weathered rock | 9.50 | m |
- ✓ Borehole reached weathered rock
Method, formulas and assumptions
- Total depth = MAX([t.zb]) = 14 m
- Lowest N = MIN([t.N]) = 4
- Groundwater RL = 4.5-1.8 = 2.7 m AHD
- Depth to weathered rock = MIN([t.rk]) = 9.5 m
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.