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Comparison of different methods for tunnel undercrossing urban road.
| Method | Cover depth | Construction cost | Construction time | Cross-section layout | Space utilization | Construction land |
|---|---|---|---|---|---|---|
| Shield tunneling | 0.8D ~ 1.0D or > 6 m15 (Deep) | High | Medium | Inflexible | Low | Big |
| RBJ | > 2.5d + 0.5 or ≥ 3 m16,17 (Medium) | Medium | Long | Inflexible | Low | Big |
| MPJ & JAS | < 2 m (Shallow) | Low | Short | Flexible | High | Small |
aD: tunnel diameter.
bd: pipe-jacking diameter.
