Structures in Kansai New Collection

+++ Evolving Civil Engineering +++

‚tunnels

- passage, flow

Underground reservoirs to prevent flooding
Japanese cities with a high density of buildings have experienced flood damage many times in the past. To protect the lives of residents and prevent the loss of assets, a new idea was developed-underground tunnel reservoirs. Water from heavy rains is temporarily stored in underground tunnels, and when conditions improve, the stored water is pumped out and released into rivers. A shield tunneling method was used to dig through muddy soil. Japanese tunneling methods, which take into account land contours and geological features, are the most progressive state of the art in the wold.

Neya river basin underground flow through a shield tunnel (Osaka Prefecture) Photo: Kajima Corp.

Completed 1999

Kobe Kou Minatojima Tunnel
An undersea tunnel made using immersed tunnel method to link Immersed Tube. The Immersed Tube use full sandwich construction, the world's first, and V-block construction was used for the last joint. All of this is state-of-the-art technology. Port Island to Shinko Higashifuto, Kobe( Dept. of Port and Urban Projects, Kobe City Tel: 078-322-5685)
Design/construction	Dept. of Port and Urban Projects and Kobe City Ministry of Transport Third Harbor Construction Bureau
Total length	approx. 1,600m (channel crossing length 520 m)
Vehicle lanes	3.25 m x 4 lanes (two lanes each upper and lower levels)

Completed 1997

Osakako Sakishima Tunnel
Japan's first undersea tunnel built using submerged construction methods, it features two lanes for vehicles on both sides of the subway line. The 2,200 m tunnel is one of the longest in the world, with about 1,000 m submerged. Minato-ku to Suminoe-ku, Osaka(Osaka City Port and Harbor Bureau Tel: 06-6572-2634)
Design	Ministry of Transport Third Harbor Construction Bureau
Construction	Ministry of Transport Third Harbor Construction Bureau and Harbor Authority, Osaka City
Tunnel length	Road approx. 2,200 m (submerged portion 1,033 m, terminal railway approx. 2,400 m)
Construction method	submerged construction (sea bottom portion approx. 1,000m)
JSCE Outstanding Civil Engineering Achievement Award (1997)