[U/C] M2 North-South Motorway

[Spotto]

Hopefully once Torrens to Darlington begins the government will set to work planning the next big infrastructure project so we can retain the skills gained from this project and roll that expertise over to the next project. Likewise with the group that will be grade separating the tram line.

A continuous pipeline of works is the only sensible way to build big infrastructure.

Agreed. If this will be done by 2030, we should be planning now for the city rail tunnel to start from about the same time if not earlier. Complete it by 2036 for the state's bicentennial.

Was about to post the same thing, with 3 TBM's they should start looking at rail infrastructure next.

Train tunnel TBMs are much smaller than motorway TBMs, significantly since we’re talking a three-lane motorway.

The tight turns that a city rail tunnel would need to make would also be far too tight for such a massive TBM.

[SouthAussie94]

Not an expert by any means, however my understanding is that the TBMs get buried on site as is too complex/costly to remove / reuse and have been designed for a specific purpose?


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3x TBMs, 4x tunnels. So at least one of the TBMs will be reused?

Yes again not an expert, however that is built for the same project and being used in a very close proximity.

Nevertheless happy to hear from anyone with experience in the field or if someone wants to query this with DIT direct.


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A rail tunnel would have a smaller diameter than a 3 lane motorway. Unlikely that the NS Motorway TBMs could be used for a rail tunnel.

[Vasco]

ABC 891 radio will be discussing TBMs with the consortium director just after 9am.


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[Nort]

Shame for the West Thebby, looks like they are being demolished for a left turn lane onto the surface road.

Shared use path at James Congden feels a bit poorly designed. If the most recent (and presumably final) renders are accurate then it's a very long length that will be very exposed to rain, wind, and sun, not great for pedestrians being funneled onto it. Especially since I'm suss that the greenery shown in that area will be anywhere near what is shown based on the precedent of other sections. Far more likely to be an expanse of gravel with a few weeds.

Hopefully the government is going to take school zone catchments into account. Looks like kids getting across South Road to Richmond Primary School will now involve seven(!) distinct crossings in a row.

[Pistol]

Agreed. If this will be done by 2030, we should be planning now for the city rail tunnel to start from about the same time if not earlier. Complete it by 2036 for the state's bicentennial.

Was about to post the same thing, with 3 TBM's they should start looking at rail infrastructure next.

Or SE Freeway link to NS Motorway?

This.
Link the SE Freeway via a tunnel under Cross Road

[dbl96]

Was about to post the same thing, with 3 TBM's they should start looking at rail infrastructure next.

Or SE Freeway link to NS Motorway?

This.
Link the SE Freeway via a tunnel under Cross Road

Exactly - it would be a massive waste to just bury the TBMs. I can't beleive DIT could be rationally considering such a stupidly wasteful option. Why on earth would they not reserve them for use on future projects? Sure, they might not be the right fit for the city rail tunnel, but there are other road projects down the track, like the SE Freeway - South Road connection which they could surely be used on.

The problem is, as others have hinted to, that we don't actually have an infrastructure pipeline in this state (or in Australia as a whole tbh). Projects are announced as one-offs once the need for something to be done has become critical, but there is little long-term planning of the optimum future shape of the network and a plan for constant work towards achieving that goal. So in the case of a project like South Road, the governments attitude is once the project is finished, the project is finished. At that point they will say they have no plans for future projects...until a couple of years down they line, they announce one, and then have to reinvent the wheel and repurchase all the expensive equipment they have junked.

Shame for the West Thebby, looks like they are being demolished for a left turn lane onto the surface road.

Disappointing. There should be more effort to preserve good aspects of the existing urban form along South Road. Once the tunnels are built and the traffic removed, it will become a much more attractive place to be, and could even develop as high street in certain sections, if sufficient buildings with adaptive value are left.

In the attached image, it shows the West Thebby being replaced by a small park. While I am all in favour of green space, small parks on exposed corners like this just don't work. DIT seems to like doing this kind of thing with left over compulsory acquired land next to road projects. The new park opposite Scotty's Motel on Main North Road is a case in point. the Call me a cynic, but it seems more about them achieving some "social impact" KPI rather than achieving good outcomes in terms of the built form of the city. Who is going to want to spend time a tiny exposed park among the traffic fumes, right next tens of thousands of high speed traffic movements? They would be better off selling this land off for some kind of commercial use that can benefit from the high exposure.

Shared use path at James Congden feels a bit poorly designed. If the most recent (and presumably final) renders are accurate then it's a very long length that will be very exposed to rain, wind, and sun, not great for pedestrians being funneled onto it. Especially since I'm suss that the greenery shown in that area will be anywhere near what is shown based on the precedent of other sections. Far more likely to be an expanse of gravel with a few weeds.

Hopefully the government is going to take school zone catchments into account. Looks like kids getting across South Road to Richmond Primary School will now involve seven(!) distinct crossings in a row.

The whole section of the motorway around James Cogndon Drive will be a massive barrier to east-west pedestrian movement. There needs to be at least another pedestrian bridge - Kingston Ave to Manchester St is probably the best place.

Also, more consideration ought to be given to future redevelopment of the whole Mile End South/Keswick area as a TOD, and how South Road fits in with this. Mile End/Keswick is probably the biggest opportunity for well-located infill development anywhere in Adelaide. It would be best if the new road was designed in a way which complemented these opportunities rather than detracted from them.

[Vasco]

Or SE Freeway link to NS Motorway?

This.
Link the SE Freeway via a tunnel under Cross Road

Exactly - it would be a massive waste to just bury the TBMs. I can't beleive DIT could be rationally considering such a stupidly wasteful option. Why on earth would they not reserve them for use on future projects? Sure, they might not be the right fit for the city rail tunnel, but there are other road projects down the track, like the SE Freeway - South Road connection which they could surely be used on.

The problem is, as others have hinted to, that we don't actually have an infrastructure pipeline in this state (or in Australia as a whole tbh). Projects are announced as one-offs once the need for something to be done has become critical, but there is little long-term planning of the optimum future shape of the network and a plan for constant work towards achieving that goal. So in the case of a project like South Road, the governments attitude is once the project is finished, the project is finished. At that point they will say they have no plans for future projects...until a couple of years down they line, they announce one, and then have to reinvent the wheel and repurchase all the expensive equipment they have junked.

The comment around burying TBMs was not in regards to comments made by DIT, it was a generalisation as to what sometimes occurs.

The Executive General Manager of the construction consortium said on ABC radio this morning very briefly that the TBMs are purchased by the project and it is up to the Government & consortium to make a decision on what happens with them after, with an option that sometimes occurs is salvaging parts for return sale back to the manufacturer.

As it was a very brief and final question, no mention of possible use for future projects was discussed.


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[ChillyPhilly]

I too am curious for the plan for the TBms.

Here's what Victoria is doing with their Metro Tunnel project:



https://www.youtube.com/watch?v=8zhKPtYaNaM

[Nort]

I assume that a big issue with TBMs is how much time and money you have to spend getting it back above ground.

If you have a good use case for using the TBM after then could be worth it. If you don't, then you're adding more time and cost onto the project for a potentially unnecessary reason.

[dbl96]

I assume that a big issue with TBMs is how much time and money you have to spend getting it back above ground.

If you have a good use case for using the TBM after then could be worth it. If you don't, then you're adding more time and cost onto the project for a potentially unnecessary reason.

Surely its a cost that could be recouped, at the very least, by selling the machine on to someone else. These are not cheap machines by any means. To treat them as disposable seems crazy.

The must be going to extract at least one of them at one point, because there are 4 tunnels and only 3 TBMs.

[Patrick_27]

I have it on good authority that the tunnelling equipment will be buried as per most tunnelling projects that happen in Australia (source: a senior emergency service official consulted on the motorway plans). It might seem wasteful and costly but it works out to be cheaper just to acquire new machines with every required project. With regards to the three machines for four tunnels, my suspicion is they will either use one machine for two tunnels, go one way then work back the other way, or they will bring one out via the trenched motorway and go back in again at the beginning on the northern tunnels. I suspect the reason they are keeping quiet on this is because the a-typical SA taxpayer will call it out as wasteful for buying such expensive equipment only then to bury it afterwards.

[dbl96]

I have it on good authority that the tunnelling equipment will be buried as per most tunnelling projects that happen in Australia (source: a senior emergency service official consulted on the motorway plans). It might seem wasteful and costly but it works out to be cheaper just to acquire new machines with every required project. With regards to the three machines for four tunnels, my suspicion is they will either use one machine for two tunnels, go one way then work back the other way, or they will bring one out via the trenched motorway and go back in again at the beginning on the northern tunnels. I suspect the reason they are keeping quiet on this is because the a-typical SA taxpayer will call it out as wasteful for buying such expensive equipment only then to bury it afterwards.

Any idea why it is so expensive to get them out at the end? And is getting it out just too expensive per se, or just not worthwhile if there is no other project to send it to?

It's surprising it would be so difficult considering the new TBM will be built in China, disassembled, shipped here and then re-assembled. It's clearly possible to take these things apart and move them around.

[SBD]

I think I heard this morning that the TBM(s) get built in a big hole, so there's a lot of digging needed before assembly can begin.

I imagine that one of them will proceed north from the north portal of the southern tunnel to the south portal of the north tunnel - this could even be how part of the trench is excavated!

Leaving them underground to rust and decay does not seem like a practical solution, just in terms of where that could be since there will be a road portal right in front, and rust would eventually lead to subsidence if they drove under the end of the surface roads.

If possible, reusing some of the TBM for a future Mount Barker/Murray Bridge link would be attractive, if only the cutting head needs to be changed from western suburb silt to Adelaide Hills rock. A tunnel under Cross Road is not an attractive solution as it extends the long decline we already have problems with. A KPMG report a few years ago had a "short south" option that built a freeway from south of Mount Barker to meet the NSM in the Darlington area by a mix of bridges and tunnels. This would avoid the long steep grade, and provide an alternate route from Mount Barker and Murray Bridge to city and suburban destinations for both commuters and road freight.

[Goodsy]

I think I heard this morning that the TBM(s) get built in a big hole, so there's a lot of digging needed before assembly can begin.

I imagine that one of them will proceed north from the north portal of the southern tunnel to the south portal of the north tunnel - this could even be how part of the trench is excavated!

Leaving them underground to rust and decay does not seem like a practical solution, just in terms of where that could be since there will be a road portal right in front, and rust would eventually lead to subsidence if they drove under the end of the surface roads.

If possible, reusing some of the TBM for a future Mount Barker/Murray Bridge link would be attractive, if only the cutting head needs to be changed from western suburb silt to Adelaide Hills rock. A tunnel under Cross Road is not an attractive solution as it extends the long decline we already have problems with. A KPMG report a few years ago had a "short south" option that built a freeway from south of Mount Barker to meet the NSM in the Darlington area by a mix of bridges and tunnels. This would avoid the long steep grade, and provide an alternate route from Mount Barker and Murray Bridge to city and suburban destinations for both commuters and road freight.

They don't "bury" them, they drive them into the ground in a burial chamber and concrete them in. The British did it after the Channel Tunnel with their TBM's. Interestingly enough the French recovered theirs

[VinyTapestry849]

If I'm correct, these TBM's will be one of, if not the largest TBM's that have ever operated in Australia

And we'll have three of these record-breaking large machines, how cool