Research Article
Force and Deformation Characteristics during the Reconstruction and Expansion of Shallow Single-Tube Tunnels into Large-Span Multiarch Tunnels
Table 3
Parameters of the surrounding rock and support structure.
| | Material | Specific weight (kN/m3) | Elastic modulus (GPa) | Poisson’s ratio | Internal friction angle (°) | Cohesion (MPa) | Thickness (m) |
| | Surrounding rock | 27 | 20 | 0.25 | 50 | 1.5 | — | | Initial support of the original tunnel | 23 | 23 | 0.2 | — | — | 0.45 | | Middle partition wall | 23 | 31 | 0.2 | — | — | 2.4 | | Initial support | 23 | 23 | 0.2 | — | — | 0.15 | | Secondary lining | 23 | 29.5 | 0.2 | — | — | 0.4 |
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