Investigations for Proposed Upgrade of the Homer Tunnel, New Zealand

摘要

The Homer Tunnel is located in a remote area of the South Island of New Zealand and carries largernnumbers of tourists to Milford Sound through an avalanche prone area. The tunnel is 1280 m longrnwith a steep ten per cent unidirectional grade descending to the west. Construction of the tunnelrnbegan in the 1930s and was completed to a nominal 6 m width in 1954. In 1996, two passing bays werernstripped-out to accommodate bi-directional fl ow of tourist coaches. During all phases of constructionrnand widening there have been episodes of strain bursting.rnThe condition of the tunnel and standard of internal services is below current internationalrnpractice, principally in terms of; in-tunnel air quality, fi re life safety, ground support, and road safety.rnA number of near-miss events have occurred involving coach fi res on the approaches and insidernthe tunnel. The national road authority, NZTA, is considering a substantial investment to improvernamenity and safety of the tunnel.rnThis paper describes the rationale for the proposed upgrade works and the investigations undertakenrnto enable that design. A holistic approach to road tunnel safety has been adopted that balances thernkey interrelated safety drivers, namely; tunnel lining, traffi c operations, ventilation, power supplyrnand egress while ensuring continuity of safe access to Milford Sound.