Inputs
3 columns on large screens, 2 on medium, 1 on mobile.
Example Data Table
The row below is computed from the default example inputs.
| H (m) | Zw (m) | φ (deg) | γdry (kN/m³) | γsat (kN/m³) | q (kPa) | Condition | Resultant (kN/m) | Base p (kPa) | z̄ from top (m) |
|---|---|---|---|---|---|---|---|---|---|
| 4 | 2 | 30 | 18 | 20 | 10 | active | 75.75 | 41.75 | 2.68 |
If you switch to imperial units, run a calculation to export in those units.
Formula Used
- Earth pressure coefficient: Ka = tan²(45° − φ/2), K0 = 1 − sin φ, Kp = tan²(45° + φ/2).
- Effective vertical stress: σ′v(z) uses γdry above Zw and γ′ below Zw, where γ′ = γsat − γw.
- Lateral pressure: p(z) = max(0, K·σ′v(z) − 2c·√K + K·q) + u(z).
- Pore pressure: u(z) = γw·(z − Zw) for z > Zw, else 0.
- Resultant force per wall length: P = ∫ p(z) dz, computed numerically (Simpson’s rule).
- Resultant location: z̄ = (∫ p(z)·z dz) / P.
- Strut load (quick estimate): Strutᵢ ≈ P · s · factorᵢ, with factors summing to 1.0.
Temporary works design may require staged excavation, code-specific pressure envelopes, deformation limits, and groundwater control assumptions.
How to Use This Calculator
- Select units and an earth pressure condition.
- Enter excavation depth and water table depth.
- Provide soil properties: φ, γdry, and γsat.
- Add surcharge and cohesion if applicable.
- Set strut levels and spacing for quick strut loads.
- Optionally enter allowable capacities for utilization checks.
- Calculate, then export results to CSV or PDF.
Always confirm with your geotechnical report and temporary works procedures.