Allandale25
Superstar
Latest Crosstown video.
|
|
|
coopEng
Active Member
None - once they dig far enough down to expose them, they just smash into them and toss 'em
Leo_Chan
Senior Member
So they dig from the surface down to remove the tunnel the TBM made? I thought these were removed from underground within the tunnel or mined from next to the tunnels.
KevinT
Senior Member
Leo_Chan
Senior Member
I general understand the process, but I was just wondering about the removal of the TBM tunnel segments specifically.
Aplus23
Active Member
Well you don't actually need a precast tunnel inside a station box, so yeah they dig down and around and dispose of the section where the platforms will be. Same thing for a mined station as well
officedweller
Senior Member
That's what they did for the Canada Line in Vnacouver.
Here are a couple of old pics from Vancouver City Centre Station.
The first time through the station site, the TBM laid tunnel to push off of,
the second time, the station was already built up, so they built a steel frame
for the TBM to push off of without laying tunnel segments.
mr.x;12563789 said:
mr.x;13069968 said:Vancouver City Centre Station opening
But the second time the TBM went through the station, the station had been partially built, so they used a steel frame for the TBM to push off of:
officedweller;17771403 said:The TBM has started boring again at Vancouver City Centre Station. They have built a steel frame (square, black) off of which the TBM "pushes" in order to get the pressure to grind against the leading edge. You will recall that when the TBM went through the last time, they laid a tunnel tube the whole length of the station. That probably wasn't possible this time given the station superstructure around it. You can see the framework being built in this Tafryn pic (the concrete collars have now been inserted from the steel frame to the station wall).
Last edited:
BurlOak
Senior Member
There is a headwall perpendicular to the direction of the TBM. If you have plenty of space, there could be side slope beyond this headwall, but generally it also has wall parallel to the direction of TBM to retain slopes. As the TBM enters this space beyond the headwall, it can be removed. The entire TBM does not have be be out - as soon as 1 segment of the TBM pokes through the headwall, it can be removed. This means the TBM extraction site does not have to be huge.
Steve X
Senior Member
ML went with this approach back in 2010 to save some money. They contracted out tunneling separating before Crosslinx build the stations.
You realized if they were dismantle from instead the tunnel, the tunnel would be in jeopardy of collapsing. For mining to be completed safely (as shown in the video), they need to install a pipe roof on top of the section before they removed the tunnel liners under it. Thus it cannot be done initially from inside the tunnel.
jcam
Active Member
As I recall, way back, there was an early batch of tunnel segments that didn't meet the specs for whatever reason. The idea at the time was to use them at the station locations, knowing they'd be sacrificed later. Smart move if that's what actually happened. Its possible because the ring is a universal design, all with a slight taper. if you want a straight section, you oppose the tapers from one ring to the next. You build up the tapers to achieve a particular curve in any direction (up, down, side). At least I think it was a universal ring design.
smallspy
Senior Member
That's precisely the case. There are 7 individual sections which are bolted together to make up a ring, and something like 17 different permutations in terms of how they can be arranged to allow them to run straight or various curves.
Dan
Toronto, Ont.
Allandale25
Superstar
New Crosstown video posted two days ago:
raptor
Senior Member
Just posted on twitter:
Note the nice graffiti on the right wall. I can't believe they posted this photo on twitter.
Note the nice graffiti on the right wall. I can't believe they posted this photo on twitter.
raptor
Senior Member
they just posted a cleaner version:
Monarch Butterfly
Superstar
Just posted on twitter:
Note the nice graffiti on the right wall. I can't believe they posted this photo on twitter.
Wonder what's behind the insulation, drywall, or paint of many formerly rundown buildings?
Did you know that when the TTC purchased 48 used PCC streetcars from Birmingham Transit Company (4700-4747 [class A-13]) by 1953, the TTC had to get rid of or paint over the segregated sections. See link.