Melb CityLink’s First Tunnel Open

Melbourne CityLink’s first tunnel opened to traffic April 16. The Domain tunnel, 3-lanes wide 1.6km (1mi) long goes under the Yarra River and Domain Gardens, beautiful landscaped river frontage and botanic gardens where no one would contemplate surface roadways. The opening of the tunnel allows traffic on the southern leg of CityLink to travel inbound to the city from the southeastern suburbs for the first time. It links 6-lane radials to the west and southeast

The tunnel was mined under the gardens using roadheaders but the under the river section was cast-in-place in a coffer dam. It was finished and ready for traffic in December last year. Opening was delayed by arguments over calculation of air emissions from the ventilation tower with environmental regulators holding up permits. The Independent Reviewer also was not satisfied that the systems for traffic control and tolling were adequate.

The office of the Independent Reviewer, half-paid for by the concessionaire and half paid by the state of Victoria under the concession agreement and enabling legislation, has to sign off on all aspects of the works before they can be opened.

There has also been concern over the adequacy of toll management software to handle the greater complexity of trips when the Southern Link is added to the Western Link - open to traffic since August and tolling since the turn of the year. The Western Link consisting of four sections is mostly elevated and provides a western bypass around the central business district to the southeast and west and connections to the airport and highways north.

Still missing is the eastbound part of the southern link. This awaits fixes to the 3.4km (2.1mi) long Burnley tunnel, 3-lanes wide that is located slightly north of the Domain tunnel and which is fully mined and goes deep under inner suburbs of Melbourne as well as the river and gardens. Water leakage into the tunnel had to be fixed with grouting. Water pressure lifted some of the massive floor slabs. They are being replaced and rock-bolted down.

The Burnley tunnel is the world’s longest 3-lane wide tunnel. It has an intermediate ventilation tower and was mined with roadheaders through greatly varying soil and rock. The Domain tunnel is shorter because it is supplemented by an old riverside expressway built in the 1960s and modified by the CityLink project – one thoroughly ugly part of an otherwise aesthetically well done project.

Present estimates are that the Burnley tunnel fixes should be ready by September allowing the whole roadway to be opened later this year.