Toronto Spadina Subway Extension Emergency Exits | ?m | 1s | TTC | IBI Group

[W. K. Lis]

The TBM's used to tunnel under the English Channel (The Chunnel) are still there. If you can get at them, that is.

From wiki.answers.com, at this link:

In late 1990, the service tunnel was almost complete. The moles had approached each other closer to the British end. France, however, didn't gloat in its accomplishments. Both countries had come together for a common good. This isn't to say that some friendly competition hadn't fueled the tunnel's construction. When the two tunnel boring machines were about 50 meters from each other, the English moles drove off-line to the right into the narrow gap between the service tunnel and the running tunnel south (Fetherston, p. 342). The British machine stopped once it lay parallel and head to tail with the French machine. The English mole was stripped of anything salvageable. It was then entombed within concrete. The French tunneling machine than was hollowed out. Its outer shell would serve as the tunnel lining.

In other words, the TBM's are recycled.

 

[rbt]

The TBM's used to tunnel under the English Channel (The Chunnel) are still there. If you can get at them, that is.

They're also done. TBM's get a lifespan of about 30km and the channel TBM's would have each bored about 20km.

 

[nfitz]

In Toronto's previous tunnelling exercises we target the sandy/clay segment which covers the city at varying depths. While condos don't sample as deeply as you might want for subway construction, they (the ones I've followed) haven't found anything unusual between Richmond Hill and Finch for soil. It's pretty safe to assume that our "crap-dirt" vein will exist for the Yonge extension but we have not taken soil samples to determine at exactly what depths it exists.

It does get more interesting the further north you get on Yonge, particularly on the north side of Richmond Hill, as you get into some channel deposits (the Yonge Street aquifer), however that's not an issue until Stouffville Road or so.

It might not be too bad if you don't get too deep ... but if you do start getting below the Newmarket Till and penetrating the Thorncliffe Sands, you can get some relatively high pressures and even artesian conditions, as you go up the hill from Clarke to Major MacKenzie, which could get uglier. It all depends how deep they are drilling, and what the TBMs are design for.

Eglinton is interesting too ... I haven't seen any good cross-sections, but I've drilled before in the Bayview/Eglinton area, and I've never seen so much flowing sand before at depth. No core recovery, just a bit if soupy sand in the barrel. I haven't looked at what's been published for this site, but I don't envy anyone trying to build a station at Bayvew/Eglinton!

 

[Transportfan]

Yonge extension shouldn't open without the DRL.

Nothing says they can't start the tunnels on Yonge first. Yonge is ready to be tunnelled but the DRL isn't.

Just curious, if the TTC just bored the tunnels for the Yonge extension so they could reuse the Spadina TBM's, and left them until the DRL is complete, could they use one launch shaft and bore the whole extension length in one go?

 

[nfitz]

Just curious, if the TTC just bored the tunnels for the Yonge extension so they could reuse the Spadina TBM's, and left them until the DRL is complete, could they use one launch shaft and bore the whole extension length in one go?

Probably not. Go read the EA, the details are in there. It's a mixture cut-and-cover and TBM. Isn't it cut-and-cover to north of Cummer?

It would be a very odd thing to do ... it's a multi-billion program, to save what, the $30-million or so value left in the TBMs? Isn't that like buying a $1,000 plane ticket to London to take advantage of a £5 remaining balance on your Oyster card?

 

[Transportfan]

I was refering to just the tunnels, not the stations, which could be dug out later. I don't think there's any cut-and-cover, except for of course, the stations. The cut-and-cover section you may be thinking of may be the short stretch to connect Cummer station to Finch's extra-long tailtracks which stretch almost all the way north to (not of) Cummer.

If the DRL-needs-to-be-completed-first is the main reason for not building the Yonge extension sooner rather than later, reusing the TBM's by boring the tunnels earlier is a good enough reason to save money, not to mention keeping ahead of future construction costs.

 

[nfitz]

I don't think there's any cut-and-cover, except for of course, the stations.

And yet I recall some cut-and-cover sections in the EA. If you don't believe me, go read it.

I don't understand this TBM recycling thing ... It's such a minor factor.

 

[M II A II R II K]

Maybe keeping the TBMs and use them for continuous tunneling and then they can go back to those tunnels when they're ready to finish the lines and extensions later.

 

[adeel]

im not qualified to say about this whole TBM business in terms of the ability to reuse to save money...but im really disliking the analogies that somehow the possibility that we can save 1% of the cost is not that important because its only 1%...its still 30M that could be deployed elsewhere...i'd be happy to schedule things in a way to save that 30M.....

 

[smallspy]

im not qualified to say about this whole TBM business in terms of the ability to reuse to save money...but im really disliking the analogies that somehow the possibility that we can save 1% of the cost is not that important because its only 1%...its still 30M that could be deployed elsewhere...i'd be happy to schedule things in a way to save that 30M.....

The thing is, it isn't just the $30M cost of the TBMs. They are only one, small portion of the cost.

You have to also pay for power, crews, tunnel liners, mucking equipment, spoil disposal, etc. All of that ancillary stuff needs to happen as soon as you begin to run the machines, regardless of whether you are putting in the subway systems right after the machine passes, or 10 years down the line.

Dan
Toronto, Ont.

 

[AlvinofDiaspar]

Twitterverse is suggesting that there is a media event on subways (subway extension?) this morning with Wynne attending (but not Ford). Does anyone know what's going on?

AoD

 

[W. K. Lis]

Twitterverse is suggesting that there is a media event on subways (subway extension?) this morning with Wynne attending (but not Ford). Does anyone know what's going on?

AoD

Apparently, Rob Ford did make it.

 

[nfitz]

The Transport Canada news release is:

http://www.newswire.ca/en/story/112...for-the-toronto-york-spadina-subway-extension

Seems it's the launch of the TBMs from Highway 407 station to Steeles West. This stage of the tunelling is 100% outside the City of Toronto, with the extraction point just north of the Steeles Avenue.

Interesting that the press release refers to the station as Steeles West instead of Black Creek Pioneer Village. I guess someone in Ottawa didn't get that memo.

 

[M II A II R II K]

CTV News had a Talkback Toronto about where the next subway should be.

 

[gweed123]

CTV News had a Talkback Toronto about where the next subway should be.

What was the consensus? (If there was any)