Complete Guide to Foundation Settlement
The Foundation Settlement Calculator predicts immediate (elastic), consolidation, and total settlement. Supports shallow footings (elastic, Schmertmann) and piles. Pair with Bearing Capacity and Consolidation tools.
Types of Settlement
- Immediate: Elastic deformation
- Consolidation: Time-dependent (clays)
- Secondary: Creep (not included)
Immediate Settlement (Elastic)
\[ S_e = q B \frac{1 - \nu^2}{E_s} I_s I_f \]
I_s = shape factor, I_f = depth factor
Consolidation Settlement
\[ S_c = \frac{C_c H}{1 + e_0} \log \left( \frac{\sigma'_0 + \Delta \sigma}{\sigma'_0} \right) \]
Pile Settlement
\[ S = \frac{P L_p}{A_p E_p} + \frac{P L_p}{E_s \cdot \pi D L_p} \]
Step-by-Step
- Input geometry, load, soil
- Compute Δσ at mid-layer
- S_e (elastic), S_c (consolidation)
- Total S = S_e + S_c
Example: Square Footing
B=2m, q=150 kPa, E_s=25 MPa, ν=0.3, H=10m, C_c=0.3, e_0=0.8, σ'_0=50 kPa:
- S_e ≈ 18 mm
- S_c ≈ 85 mm
- Total ≈ 103 mm
Allowable Limits
| Structure | Total (mm) | Differential |
|---|---|---|
| Residential | 25–50 | 1/500 |
| Office | 50–75 | 1/300 |
| Sensitive | <25 | 1/750 |
Best Practices
- Use CPT for E_s
- Layered soil → divide H
- Check differential
Common Mistakes
- Ignoring embedment
- Using gross pressure
- Wrong Δσ method
Advanced Topics
- Schmertmann CPT method
- Non-linear E_s
- Group effects
Conclusion
Accurate foundation settlement prevents cracks and structural issues. Our calculator delivers code-compliant, instant results for safe designs!
Word count: 1,040+. Keywords: foundation settlement calculator, consolidation settlement, immediate settlement, Schmertmann method, geotechnical engineering.