Title: Dacey Todman Tunnel . Eastern Distributor

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Publication: CIA

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Date: 2/13/2011

Abstract:
The recently completed Eastern Distributor toll road forms a motorway connection from the end of the Cahill Expressway at Woolloomooloo through to the Kingsford Smith Airport at Mascot. The project includes a rock tunnel through Eastern Sydney from Woolloomooloo to Drivers Triangle, southern tunnel approaches at Moore Park Road, Anzac Parade and South Dowling Street, a depressed motorway along parts of South Dowling Street beside Moore Park and a cut and cover tunnel towards the southern end of South Dowling Street known as the Dacey Todman Tunnel. The Dacey Todman Tunnel is a 600m long dual carriageway cut and cover structure built in one of the most tightly constrained areas of South Dowling Street. The tunnel provides two northbound and southbound lanes running directly below and essentially parallel to South Dowling Street. The structural form comprises external diaphragm walls and a central row of cast-in-place piles supporting a precast roof deck with a reinforced concrete base slab designed to resist uplift due to ground water. The tunnel was built using the top down construction method with the roof deck acting as a prop for the external diaphragm walls during tunnel excavation. This paper discusses some of the more interesting aspects of the design of the tunnel which forms an integral part of this award winning project.