Complete Guide to Tunnel Lining Design
The Tunnel Lining Design Calculator computes thrust, moment, and reinforcement for circular linings in rock or soft ground. Essential for NATM, TBM, and cut-and-cover tunnels. Pair with Consolidation and Earth Pressure tools.
Lining Functions
Resist ground pressure, prevent collapse, ensure watertightness.
Rock Tunnels (Elastic)
\[ p_v = \gamma H, \quad p_h = \lambda p_v \]
\[ T = \frac{p_v + p_h}{2} R, \quad M = \frac{p_v - p_h}{4} R^2 \]
Soft Ground (Full Overburden)
\[ p_v = \gamma H, \quad p_h = K_0 p_v \]
Similar T, M formulas.
Reinforcement
Whitney stress block: \[ A_s = \frac{M}{0.9 f_y (d - a/2)} \]
Step-by-Step
- Define geometry and loads
- Compute p_v, p_h
- Find T, M at crown/side
- Design section
Example: Rock Tunnel
D=5m, t=0.3m, H=20m, γ=22 kN/m³, λ=1.5:
- T = 330 kN/m
- M = 82.5 kN·m/m
- As = 850 mm²/m
Support Categories
| Rock Class | Support |
|---|---|
| Good | Shotcrete + bolts |
| Poor | Segmental lining |
Best Practices
- Monitor convergence
- Use fiber-reinforced shotcrete
- Include water pressure
Common Mistakes
- Ignoring λ ≠ 1
- No safety factors
- Wrong K₀
Advanced Topics
- 3D FEM
- Segmental joints
- Seismic response
Conclusion
Safe tunnel lining design ensures long-term stability. Our calculator delivers instant, code-compliant results for circular tunnels. Build resilient underground infrastructure!
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