Toronto Eglinton Line 5 | ?m | ?s | Metrolinx | Arcadis

[Markster]

Doom Paul is supposed to be a joke that upcoming events will have apocalyptic results. I think the joke here is 'oh my god we're building transit holy shit the end of Toronto is coming'. Sarcastically.

Don't feel like you're too old to understand this. Memes often come out of nowhere, and they often evolve in meaning over time.

The "It's Happening" gif is often used for earnest joy as well. It started off as ironic, referencing Ron Paul's failing 2012 campaign, but has morphed over time into non-irony.

 

[Tulse]

I apologize if this is a profoundly silly question that has been answered elsewhere, but: If the extraction shaft for the western TBMs is west of Yonge, and the extraction shaft for the eastern TBMs is east of Yonge, how will the part under Yonge actually be tunnelled?

 

[Tuscani01]

I apologize if this is a profoundly silly question that has been answered elsewhere, but: If the extraction shaft for the western TBMs is west of Yonge, and the extraction shaft for the eastern TBMs is east of Yonge, how will the part under Yonge actually be tunnelled?

http://wiki.godvillegame.com

 

[Markster]

I apologize if this is a profoundly silly question that has been answered elsewhere, but: If the extraction shaft for the western TBMs is west of Yonge, and the extraction shaft for the eastern TBMs is east of Yonge, how will the part under Yonge actually be tunnelled?

There are no silly questions!

Just like at Eglinton West, there are(/will be) TBM shafts on either side of the existing subway, so the TBMs don't need to interfere with the operating line.

The connecting segment will be built as cut-and-cover, part-and-parcel with the station construction. This lets them keep close tabs on the stability of the existing subway tunnel.

 

[Tulse]

But doesn't the LRT cross below the subway? How will they do cut and cover?

 

[Zach6668]

But doesn't the LRT cross below the subway? How will they do cut and cover?

Probably the same way they've managed to dig out a whole new story beneath Union Station while keeping it open.

 

[Tulse]

Probably the same way they've managed to dig out a whole new story beneath Union Station while keeping it open.

But I thought that "cut and cover" referred specifically to creating a tunnel by digging a trench from the surface down to the level one wanted, then covering over the exposed section. And that won't work if the subway crosses above the level of the LRT tunnel.

 

[crs1026]

But I thought that "cut and cover" referred specifically to creating a tunnel by digging a trench from the surface down to the level one wanted, then covering over the exposed section. And that won't work if the subway crosses above the level of the LRT tunnel.

It does, but bear in mind that in conventional cut and cover, the excavation may unearth things like sewers and water mains, and just leave these hanging in mid-air (I'm exaggerating, they are braced or supported) while the excavation continues downwards. A lot of the old photos of the Yonge Subway excavation show this clearly.

Excavating under the subway is much the same, albeit a bit bigger engineering challenge. The existing subway can "hang" in the air while things are built beneath it.

- Paul

 

[Tulse]

I get that, but are you saying that they will literally be trenching across Eglinton, or instead just continuing to dig the tunnel under the surface by other methods than the TBMs?

 

[crs1026]

I get that, but are you saying that they will literally be trenching across Eglinton, or instead just continuing to dig the tunnel under the surface by other methods than the TBMs?

I'm out of my depth here, and I haven't seen the plan. But it would not be a shovelled equivalent of a TBM bore.

If you look at how they built the West Toronto Diamond underpass, they went downwards right at the crossing and put in a temporary bridging structure to support the railway tracks. Then, when the overpass proper was done, they excavated the outer ends of the trench. I could see a similar approach used here, because the central part would take the longest and require the most temporary support.

- Paul

 

[rbt]

I get that, but are you saying that they will literally be trenching across Eglinton, or instead just continuing to dig the tunnel under the surface by other methods than the TBMs?

They will literally be trenching along Eglinton across/over/under Yonge.

The area above/below the subway line will be hollowed out, and the Yonge line reinforced structurally as they go. The new station will be built around the now reinforced section of Yonge line.

The risk of a Yonge line collapse using a TBM underneath the Yonge line is very high. Toronto soil is sloppy and requires a very large buffer to prevent existing structures from moving. This is, in fact, why Eglinton is 2 small bores instead of 1 large bore; small bores require much smaller buffer distances.

 

[JayBeeGooner]

The tunnels will be underpinned. Similar to how the Bloor Danforth was tunneled under the Yonge Line and the University Line at the time.
I believe there is a pic out there that shows the construction.

 

[Steve X]

It does, but bear in mind that in conventional cut and cover, the excavation may unearth things like sewers and water mains, and just leave these hanging in mid-air (I'm exaggerating, they are braced or supported) while the excavation continues downwards. A lot of the old photos of the Yonge Subway excavation show this clearly.

Excavating under the subway is much the same, albeit a bit bigger engineering challenge. The existing subway can "hang" in the air while things are built beneath it.

- Paul

I imaging they'll just going to do shoring. Instead of vertically, they'll excavate both sides and drill horizontally under the tracks and apply a layer of concrete. Then they can dig underneath. It's be similar to some of the mined stations. I believe they'll have an open house next week for Eglinton West.

 

[nfitz]

I apologize if this is a profoundly silly question that has been answered elsewhere, but: If the extraction shaft for the western TBMs is west of Yonge, and the extraction shaft for the eastern TBMs is east of Yonge, how will the part under Yonge actually be tunnelled?

It won't be. The station box between the two extraction shafts will be excavated - as the "diameter" is much larger than the TBM.

It's going to be a massive project - with the plan to move the existing Yonge line platforms at the same time.

I'm not even sure if it's part of the Crosslinx contract. Originally there was talk of TTC tendering this station (and Eglinton West - or whatever bizarre name that one is now) separately, so that Crosslinx didn't interfere with the existing line - but I'm not sure where that landed.

 

[barit]

It won't be. The station box between the two extraction shafts will be excavated - as the "diameter" is much larger than the TBM.

It's going to be a massive project - with the plan to move the existing Yonge line platforms at the same time.

I'm not even sure if it's part of the Crosslinx contract. Originally there was talk of TTC tendering this station (and Eglinton West - or whatever bizarre name that one is now) separately, so that Crosslinx didn't interfere with the existing line - but I'm not sure where that landed.

Not so much "move" the platforms but extending them north 30 metres.