hawc said:
I keep trying to visualize in my head where exactly the tunnel hole is going to be on that hill. Is it going to kind of be near the top or punch out midway down? Can't picture it. Also are they pulling the tunnel boring machines out at this place?
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You can see the portal location in this rendering.

The TBMs would be taken out in the same structure - just a bit further south.

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So it appears then the the tunnel opening will be almost 'cut & cover' rather than coming out of the vertical face of the hillside with undisturbed earth on top. It will likely just be a big section dug down and out at the opening. Fun how it goes straight from tunnel to bridge like on the Bloor Viaduct.
 
hawc said:
So it appears then the the tunnel opening will be almost 'cut & cover' rather than coming out of the vertical face of the hillside with undisturbed earth on top. It will likely just be a big section dug down and out at the opening. Fun how it goes straight from tunnel to bridge like on the Bloor Viaduct.
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The tunnel opening at the Bloor Viaduct is cut-and-cover. Most of Line 2 is cut and cover.
 
hawc said:
So it appears then the the tunnel opening will be almost 'cut & cover' rather than coming out of the vertical face of the hillside with undisturbed earth on top. It will likely just be a big section dug down and out at the opening. Fun how it goes straight from tunnel to bridge like on the Bloor Viaduct.
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AFAIK tunneling machines that aren't just buried will always finish their drives at a headwall and the rings the TBM places come right up to that headwall. That implies that when emerging from a slope, you've always got to dig some kind of extraction shaft that is at least the length of the machine that advances ahead of the rings. Then you can't bring it too close to that slope either, lest you risk disturbing top soil and create a dangerous situation for the DVP, that dictates the additional distance your headwall will sit back from the slope.

I suppose they could just cut from the headwall and leave an open trench, but whether they want to reclaim space above for roads, housing, parks, or just put that noisy tunnel opening further from homes, they've chosen to cover to finish here.
 
Interesting. Are the machines re-used? If not, could they not just take a thermal lance and cut it up for scrap inside the tunnel?
 
hawc said:
Interesting. Are the machines re-used? If not, could they not just take a thermal lance and cut it up for scrap inside the tunnel?
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Some machines are reused, I remember we sold those used for building the TYSSE and that they were being refurbished for use. Don't think we ever buried any of our machines as I recall it being discussed for the Crosstown machines at Yonge, but I think we at least salvaged the pieces since it came into the station box.

I'm no tunneling expert but I assume when you bury it you can't safely extract the pieces ahead of your tunneling rings as the physical machine is the thing keeping the tunnel from collapsing in on that section. The business end doesn't live in the tunnel, but out ahead and in non-stabilized earth, and since the TBM is larger than the outside of the rings, you can't really throw it in reverse either.
 
Demolition of the Dundas bridge (north/west side) coming in 2 weeks.
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The temp ped bridge at Exhibition is open after being closed all winter and the views are pretty great now that excavation has started!

Looking East
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Looking West
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hawc said:
Interesting. Are the machines re-used? If not, could they not just take a thermal lance and cut it up for scrap inside the tunnel?
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Not always. I'm not sure if the ones used for doing the Exhibition to Corktown segment will then be the ones used do the Pape to DVP section.

If they don't re-use, and they haven't got an extraction option, I'd think they'd just do the normal dig themselves into the side somewhere and be entombed.
 
nfitz said:
Not always. I'm not sure if the ones used for doing the Exhibition to Corktown segment will then be the ones used do the Pape to DVP section.

If they don't re-use, and they haven't got an extraction option, I'd think they'd just do the normal dig themselves into the side somewhere and be entombed.
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All the south TBMs are being extracted at the excavated Queen station site. I highly doubt they plan to slow work down by waiting for this to finish before tunnelling the east.
 
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