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Freezing to Tanking: Challenges of the City Link Driven Tunnels

Daniel N. Adams
Jacobs Associates,
San Francisco, California

Bruce Hutchison
Senior Geotechnical Engineer, ABM Savage River Mine,
Box 659, Tasmania, Australia

Clive Wilson
Wilson Pass, Inc., 14 Palm Springs Road,
Durban, South Africa


 

Two three-lane highway tunnels, 700 and 2900 m long, make up the driven tunnels portion of Melbourne City Link. Tunnel construction, using design-construct delivery, commenced in May 1996. Construction required excavation through varying rock conditions; temporary support included ground freezing, pipe-spiling, steel sets, and rock bolts. Permanent support for the tunnels required both drained and undrained tunnel cross sections using unreinforced concrete. This paper reviews the construction methods, and highlights some of the not-so-standard designs developed while construction was underway.