After two years of construction, one of the world’s widest tunnels has been completed eight months ahead of schedule.The 1.7km long, 24.5m wide tunnel in Sydney, Australia, forms an integral part of the US$448m, 6km long Eastern Distributor and was originally due for commissioning in August 2000.
The tunnel is part of a new route that forms an unbroken link between the CBD and the airport and the south-eastern suburbs.
Construction was undertaken from two headings – in the north by Concrete Construction using three roadheaders and from the south by excavation sub-contractor McConnell Dowell using two roadheaders and a conveyor system to load spoil.
Excavation was carried out through generally favourable sandstone, although on the northern heading one fault zone and a dyke required canopy tubes and steel sets as support. The final lining comprised shotcrete and rockbolts.
To mark the opening, 60 000 people walked through the tunnel before the first of the anticipated 30 000 daily vehicles. Two more traffic tunnels are being planned by the New South Wales government as part of a Sydney orbital road network.
