Swanston St tunnel excavation (Vic.)

Roderick.

July 9 2017 Metro Rail: Tunnel dig will see 438,000 trucks through CBD over four years .
It's the Andrews government's marquee project, an $11 billion rail tunnel that will ease congestion on the metropolitan rail network for decades.
But engineers who have worked on the Metro Tunnel fear Melbourne's CBD will become clogged with trucks as the state government races to meet three deadlines it has placed on the project – to have construction underway in 2018, to have key tunnelling completed through the CBD by 2022, and the network operating in 2026.
A cement truck delivering cement to a building site in the Melbourne CBD. Photo: Jesse Marlow
Under Victoria's fixed four-year terms of government, all three happen to be election years.
The Sunday Age can reveal that, in order to meet those deadlines, the CBD's already congested roads will have a further 438,000 trucks added to the traffic burden over the four years of tunnelling work, as dirt, rock and supplies are trucked through the heart of the city.
The CBD's roads will have a further 438,000 trucks added to the traffic burden over the four years of Metro rail tunnel work. Photo: Craig Sillitoe .
Those trucks will run through the CBD every five minutes, 24 hours per day, for four years, and will impact the city's commuters, office workers, residents and retailers.
According to one engineer who has worked on the planning for the project, that truck burden is only necessary due to the tight deadline placed on the project by the Andrews government.
He claims the state government's decision not to use advanced tunnel boring machines (TBMs) to build the entire tunnel means 430,000 semi-trailer loads of dirt and rock will have to be excavated from underneath the CBD, loaded onto trucks, and driven through the centre of the city.
"The state government has requested a mined cavern design for the section of tunnel between CBD North and CBD South stations," he said.
Tunnel boring machines will not be used on Melbourne Metro tunnel. Photo: Christian Pearson .
"That means we will drop road headers under the city to build the tunnels. When you use road headers, who need to take all the spoil out through vertical shafts and truck it away. The only reason I can see for doing it this way is to meet the deadline.
"If you use TBMs, you can take the spoil back out through the tunnel you have built."
A tunnel boring machine at work. Photo: supplied .
Those road headers will be lowered underground via three giant shafts, 11 storeys deep, that will be excavated in the CBD – at Franklin Street and at A'Beckett Street, both near Melbourne Central station, and a third shaft at City Square, near Flinders Street Station.
Road headers will be lowered via those shafts and will begin the process of excavating the 2 million cubic metres of soil and rock needed to complete Metro. That's more than enough to fill the MCG to the roof, or fill 800 Olympic-sized swimming pools.
The tail end of a tunnel boring machine . Photo: Paul A Blunden .
"Under the original plan, when we were only building a shallow tunnel of 10 metres, so there was no way we would use TBMs," the engineer told The Sunday Age.
"When we moved the tunnel almost 40 metres beneath the surface, TBMs became an option, and a better option in my mind. That's because you can take the spoil back out through the tunnel, pretty much underneath the city. Instead it is going to be four years of truck hell in Melbourne."
Illustration: Matt Golding
Asked why road headers would be used instead, the engineer replied: "Time".
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TBMs can tunnel at up to 50 metres per day. Even if they achieve that maximum tunnelling rate on the Metro project, it will take many months for the tunnel borers to reach the city from either Arden or Domain.
"Using road headers means we can build the middle section of the tunnel and stations while the TBMs are approaching from each end. It shaves time off the project for sure, but the downside is the trucks."
The Environmental Effects Statement for Metro reveals the CBD section of the project will require 300 truck movements per day. That equates to one truck every five minutes, 24 hours a day, 365 days a year, for four years. Put another way, it an extra 438,000 semi-trailer trips through the heart of Melbourne over four years.
No economic or environmental modelling has been done on what impact that extra traffic will have on the city.
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Three consortia remain in the race to build the Melbourne Metro tunnel, and all have been instructed to use the "mining cavern" technique for the CBD section of the project
The reason, according to state government documents, is to "minimise the impacts on Melbourne's city centre, and specifically Swanston Street".
The favourite to win the bidding process is the Cross Yarra Partnership, which includes Lendlease, John Holland and Bouygues Construction.
It has already won the right to build vertical shafts for each station. According to sources at Spring Street, the Cross Yarra bid is also considering an extension of the road header section of tunnel, through to Parkville. That would put even more trucks on Melbourne's roads.
There are two rivals to the Cross Yarra bid.
The first is the Continuum Victoria consortium comprising Acciona, Ferrovial Agroman, Honeywell, Downer EDI and Plenary Origination.
The second is the Moving Melbourne Together consortium, which comprises Pacific Partnerships, CPB Contractors, Ghella, Salini Impregilo and Serco.
The early submissions from all three bidders are already in. They total more than 100,000 pages, and a final decision will be made on who gets to the build the project and how it will be built later this year.
The Sunday Age put a series of questions about the construction of Metro, and why road headers are being used to build the mid section of the tunnel, to the state government. The state government did not respond.
< www.theage.com.au/victoria/metro-rail-tu...20170708-gx7bv8.html >

City traffic is bad enough now, particularly with the lane closures near the shrine now.

If you were cynical and tied the "milestones' to election years you would be disgusted.
To add that many truck movements from the middle of the CBD is madness to my mind, especially when engineers say it is not the best way to do it.
SICKENING

We seem to be seeing projects based on political considerations rather than quality engineering in Victoria. IE cancellation of the East West link and the Skyrail botch up

and then the build what was to be the last stage of the East-West tunnel first as a 'new project' when the original road that was to be built to take the traffic isn't there.

proof that to be a politician you must first lose any common sense you may once have possessed!

Bruce, it seems to me that ALL parliament houses in Australia have a resident virus that turns normal, reasonable people into two faced fools when they become politicians. If you doubt what I am saying then watch parliament question time for confirmation. Splinter groups like Pauline Hanson, Nick Xenophon, Cory Bernadi etc will continue to gain support because the average punter is fed up with today'
s politics.

atkipete wrote: We seem to be seeing projects based on political considerations rather than quality engineering in Victoria. IE cancellation of the East West link and the Skyrail botch up

Classic case of "jobs for mates"

Does Metro tunnel and Skyrail mean the railways will no longer be carrying freight on the Dandenong line? Cant see how they could run diesel locos through a tunnel or carry unsecured containers on the elevated bits.
More work for the trucking sector?

Gippsland freight continues via Flinders St and the surface routes. The containers are hardly unsecured: the twistlocks are twisted, and the elevated section is no worse than Flinders St Viaduct. PTV wants to recycle the current Dandenong tracks from Flinders St to Caulfield as a VLine and freight 'fast' route, but has done nothing to allow for the extra two tracks to Dandenong.
This is all bound up with the decision re the next container port, and IA (with no expertise) is favouring bay west.
Roderick.

Roderick, I used the term “unsecured containers” after reading about that ATSB investigation into the accident at Bowser – see www.atsb.gov.au/publications/investigati...15/rair/ro-2015-013/
and others. I don’t understand how automatic twist locks work but there is a move against them now. See www.afcan.org/dossiers_techniques/twistlocks_gb.html
The ATSB website is littered (pardon the pun) with reports of freight train derailments, often due to poor equipment maintenance. Any road freight operator would be hauled before the courts in a similar scenario.

The safety aspects of Skyrail ( particularly for freight trains) need to be considered carefully and it would be a pity if this project means they can no longer operate into Gippsland.