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Deep underground (大深度地下, dai-shindo chika) is a Japanese concept for the public use of deep underground, enabled by a 2001 law. It was first thought of in the late 1980s as Japan faced ever-increasing land values in the economic bubble, to allow the use of heretofore-unused deep underground for necessary water and utility ducts and other city tunnels.

However, due to technical difficulties in ventilation, emergency procedures and other safety-related issues and the relatively high cost, no projects using deep underground have been completed as of 2010.

Definition

  • Depth greater than 40 meters or
  • Depth 10 meters greater than the layer on which deep foundation rests

In the case of public use, no compensation to the land owner is required.

Projects using the law

  • Underground water mains in Kobe ( Chūō-ku, Kobe)
    • Project approved on June 19, 2007 (first ever in Japan).
  • Tokyo Gaikan Expressway (Tōmei Junction - Ōizumi Junction/Interchange)
    • Project status elevated to construction stage on April 27, 2009.

Projects anticipated to use the law

External links