Technical specifications

Scope of work
Section 3.1: Tunnelling under the southern part of Zurich Main Station and construction of a shaft in front of the southern part,

• 220 running metres of longitudinal tunnels (excavated area: approx. 36 m²)
• 390 running metres of transverse tunnels (excavated area: 14 m² - 17 m²) as auxiliary tunnels for construction work using the topdown method under the southern part

Section 3.2: Double-track railway tunnel (main tunnel) and parallel escape and rescue tunnel, total length of main

• Tunnel: 4,537 m
  of which 4,382 m are shield-driven
  internal diameter: 9.74 m
• Length of escape and rescue tunnel: 4,460 m
  internal diameter: 4.35 m
• 8 cross-passages
• 2 emergency exits
• 105 m of conventional tunnelling between the TBM launching chamber and the cut and cover tunnel in Oerlikon
• Brunnenhof start shaft
  (diameter: approx. 23 m, depth approx. 37 m)
• 8 recesses for technical equipment inside the tunnel

Construction method
Section 3.1: Auxiliary tunnels: tunnel excavator with pipe and spile canopy support systems

Section 3.2: Main tunnel: TBM tunnelling using a convertible TBM

• operated both in hard rock mode (4,105 m)
  and in slurry mode (277 m)
• Shield diameter: 11,23 m;
• Double lining
  segmental lining with in-situ concrete inner lining with external water proofing
• Escape and rescue tunnel: 4,390 m
  constructed by a Gripper-TBM and 70 m using a road header
  TBM diameter: 4.75 m
  lining: shotcrete with wire mesh reinforcement and anchors

Geology
Section 3.1: Ground moraine (glacial gravels)

Section 3.2: Rock (molasse) and loose rock (gravel, lake sediments)