ABSTRACT
The Cross City Tunnel comprises 2 km of a new underground traffic route in Sydney, Australia. The route is complex and involves six tunnels driven through Hawkesbury Sandstone beneath the city streets of the Central Business District. The tunnels include two main carriageways, three entry/exit ramps, and a ventilation tunnel. They pass alongside more than 200 buildings, many in excess of 20 storeys. The tunnel design therefore involves issues of settlement control as well as rock support. The tunnel structure has an anticipated design life of 100 years. This paper describes methods of design for the shotcrete, fire resistance issues, and the specification of the shotcrete for this project.
