Research Article
Determination of the Installation Time of Secondary Liner during Excavation of Large Cross-Section Double-Arch Tunnels
Table 3
Distribution of stress release ratio in different stages.
| Plan | Stress release ratio in different stages | Accumulative release ratio (%) | Tunnel excavation | Initial support | Secondary liner |
| Plan 1 | 20 | 50 | 30 | 100 | Plan 2 | 20 | 60 | 20 | 100 | Plan 3 | 30 | 40 | 30 | 100 | Plan 4 | 30 | 50 | 20 | 100 |
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