How is the Jane-Mt Dennis tunnel going to be built? I'd hope at least that section is built as a cut-and-cover instead of getting TBMs ready and drilling for a paltry few hundred metres of tunnels.
It will have to be cut and cover or mined. Mount Dennis Station isn’t that deep under so there’s no way they can even think of TBM.
 
How is the Jane-Mt Dennis tunnel going to be built? I'd hope at least that section is built as a cut-and-cover instead of getting TBMs ready and drilling for a paltry few hundred metres of tunnels.
It will have to be cut and cover or mined. Mount Dennis Station isn’t that deep under so there’s no way they can even think of TBM.
I'm pretty sure its already been confirmed to be dug using a TBM.
 
They've only confirmed that there will be a tunnel, not what will be used to create it.

Dan

So I presume its up to the winning bidder to determine how the tunneling will be done?
 

So I presume its up to the winning bidder to determine how the tunneling will be done?
Without having intimate knowledge of the wording of the tender, that would be my assumption.

It would be a bit unusual to use a TBM for such a short distance, especially considering that the launch and retrieval pits will end up requiring almost as much distance as the length of the tunnel itself. It seems to me that this short length would be ideally suited for cut-and-cover - especially considering that the east end of the tunnel/west end of Mount Dennis Station is only covered by a couple of feet of cover. Another likely option would be to mine the tunnel as the set up costs are considerably lower than using TBMs even though the ongoing working costs are higher.

Dan
 
I'm pretty sure its already been confirmed to be dug using a TBM.
I believe there is a safety requirement on how deep the TBM needs to be before being used. That’s something like at least twice the diameter. If they just used it in shallow condition like this tunnel, all the houses will feel the vibration that can possibly knock them down.
 
I believe there is a safety requirement on how deep the TBM needs to be before being used. That’s something like at least twice the diameter. If they just used it in shallow condition like this tunnel, all the houses will feel the vibration that can possibly knock them down.

That's fair enough. I think it's safe to say this tunnel will be built in a cut-and-cover method. Though, from the Design Plates in the Environmental Assessment, it calls 300 metres of this section as a "Bored Tunnel". Please help! My brain cannot comprehend!

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That's fair enough. I think it's safe to say this tunnel will be built in a cut-and-cover method. Though, from the Design Plates in the Environmental Assessment, it calls 300 metres of this section as a "Bored Tunnel". Please help! My brain cannot comprehend!

View attachment 398149
"Bored" would imply that they are digging out the tunnel sequentially from one or both ends, as opposed to digging a trench and covering over it - the colloquial "cut-and-cover".

A TBM is one way to bore a tunnel, but by no means the only way.

Keep in mind too, that they don't have to follow the exact drawings as presented in the EA, but just to use them as a guideline. I don't know if changing from a bored tunnel to cut-and-cover would necessitate a fresh EA - others here will be able to answer that better than I.

Dan
 
Let's also bury the elevated or at-grade sections of all the other lines as well while we're at it.

Line 1 - Goodbye to the surface sections between Rosedale - Eglinton stations, and the section in between Allen Road.

Line 2? Phew, so many! Kipling to Royal York above ground sections need to be buried immediately!! Also, Old Mill station being above ground at Humber River? Preposterous! Put it deep underground, under the river!!!! Don't even come to me about the sections between Runnymede and Dundas West stations. Bury bury bury! On the east side, I don't think we can accept the line being above ground at the Prince Edward Viaduct, we need to put it all underground, beneath the Don Valley! And how dare the trains can even think of being exposed to sunlight between Victoria Park to Warden stations!

Line 3? Good planning by the power that be, by turning the elevated SRT into the far superior, deep underground, subway. Screw the money!

I think we have to go one step further and bury even the Maintenance and Storage Facilities! These subway trains should not be allowed to see sunlight when they are in service with the TTC!

Should we also let Councilor Nunziata know about all the GO tracks that are above ground?

/s

God, sorry everyone, I had to get that off my chest!
 

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