Research Article
Shield Tunneling under Railway Station Throats in Soft Soil Areas: A Case Study
Table 3
Comparison of line alignments.
| Item | Scheme 1 | Scheme 2 (selected) | Scheme 3 |
| Minimum curve radius (m) | 450 | 350 | 300 | Line shape beneath railway throat | Curvature, R = 450 m | Straight line | Partly straight; partly curvature R = 300 m | Tunneling difficulty | Average | Good | Poor | Turnouts right above the tunnels | 6 | 3 | 3 | Double-slip turnouts affected | 2 | 1 | 1 | Spatial relationship | Reference | 9–11 m to the west | 12–15 m to the west | Metro operation condition | Good | Average | Poor |
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