By Evan Tattersall
CEO of Melbourne Metro Rail Authority
As planning and design work for the Metro Tunnel project gathers pace, we are continuing to actively investigate ways to reduce and manage surface disruption during the extended construction phase of this city-shaping project.
If Melbourne is to safeguard its economic prosperity and liveability – not only for residents and businesses but also for the many people who visit the heart of the city each day for work, recreation and tourism – then this transformational piece of infrastructure is absolutely vital.
It is also urgently needed and the sooner we can deliver the new tunnels and five underground stations to enable more trains to run in and out of the city, the better.
It is true that with a project of this scale and complexity a level of disruption during its construction is unavoidable. The Melbourne Metro Rail Authority (MMRA) has always been upfront about this fact, both publicly and in our meetings with local stakeholders. We have also gone to great lengths based on stakeholder consultation and feedback to date to make innovative changes to our design and methodology to reduce and manage potential impacts.
Examples include moving the site of the new Parkville station further away from the hospitals and out of Royal Parade; using tunnel boring machines under the Yarra River instead of a more disruptive immersed tube method; and the shift away from “cut and cover” station construction for Swanston St. Each of these decisions has greatly reduced the potential for surface disruption.
We are also looking at innovative ways to reduce our potential impact on the City Square. At this stage, we believe we will temporarily require the square for around three or four years to build an entrance to CBD South station and to service the excavation of the station itself.
In addition, after 12-months of initial works to remove the public car park under the square we are looking to use an acoustic shed over the entire worksite and this will greatly reduce noise and dust issues. We are also planning to use automatic wheel washers to significantly reduce the amount of dirt and dust that is brought onto city streets.
Far from “destroying the centre of the world’s most liveable city” during construction, we expect the impact of our works will be similar to those already experienced every day on other major building sites around the CBD – particularly those involving the excavation of multi-level basement parking.
In fact, the impacts will be somewhat similar to those experienced when the Westin Hotel and its underground car park were constructed 20 years ago.
If you travel to London, New York, Kuala Lumpar, Hong Kong or numerous other cities at the moment there are similar projects underway in the centre of these high density cities.
In consultation with local residents, we have been exploring different ways to remove excavated material from CBD South Station other than using trucks, but the alternatives assessed so far would be very costly and would significantly delay the works.
It is vital that we are able to work on the station excavation from several fronts at the same time. This will reduce the duration of construction disruption and also help us to make the Metro Tunnel operational sooner.
However, we will continue to work with residents and businesses in the city, along with the City of Melbourne and the construction industry itself, to identify ways of delivering the Metro Tunnel project as cleverly and, with consideration of all issues, as quickly as possible.
In addition we are looking to take on board the best practice lessons from similar rail tunnel projects around the world and also have the benefit of a number of experienced engineers in our team who have worked on these successful overseas mega projects.
We are determined to deliver this exciting project below the city in a way that enables Melbourne to keep moving above.