File:Seikan Tunnel 3d cross section 1a.svg

A sketch (not to scale) of a typical cross section of the Seikan Tunnel, an underwater railway tunnel in Japan.

Inspiration provided by: Morse, p52, bottom figure^[1] & Paulson, figure 8.^[2]

• (1): Main tunnel. 11-11.4 metres wide. Horseshoe shape shown, but a circular cross section was used in areas with difficult geology.
• (2): Service tunnel. 4-5 metres wide. Sprayed concrete thickness 0.12-0.15 m. Horizontally, the service tunnel is located 30 m away from the main tunnel (centrelines)
• (3): Pilot tunnel. 3.6-5 metres wide. Sprayed concrete thickness 0.12-0.15 m. The depth of the pilot tunnel varies between 0 and 118 metres below the floor of the service tunnel. In the middle of the Tsugaru Strait the pilot tunnel was not constructed. Horizontally, the pilot tunnel is located 15 m from both the service and main tunnels (centrelines) - in between.
• (4): Connecting galley. Located at intervals of approximately 600m.

1. ↑ Morse, D. (May 1988). "Japan Tunnels Under the Ocean". Civil Engineering 58 (5): 50-53.
2. ↑ Paulson, B. (1981). "Seikan Undersea Tunnel". American Society of Civil Engineers, Journal of the Construction Division 107 (3): 509-525.

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