UBCx - Millennium Line Extension Arbutus to UBC | Proposed

[scottN]

Originally Posted by BaddieB

You would only need to rip out a small end of the golf course to go from 8th to the Boulevard. No need to touch the UEL forest. As for the hill, eh, I need to take a closer look, but it's a challenge boring would face anyways (just less significantly). The good thing is there's a lot of room to dig once Broadway becomes 8th, unlike digging on an artery where one has to be mindful of traffic.

Also just so we are clear, my route goes down Broadway until it becomes 8th. It would dig through that curved stretch. There would be zero need to bore at any point, as the curve brings it from Broadway to Jericho seamlessly.

A station would likely be on 8th by that field east of the tennis courts.

A cut and cover tunnel from broadway/alma to 8th avenue would have to cross the highbury interceptor, a 2.9m diameter sewer pipe underneath highbury street. I don't think that's going to work. It either has to be a deep bored tunnel underneath the sewer, or elevated above.

[MalcolmTucker]

Originally Posted by scottN

A cut and cover tunnel from broadway/alma to 8th avenue would have to cross the highbury interceptor, a 2.9m diameter sewer pipe underneath highbury street. I don't think that's going to work. It either has to be a deep bored tunnel underneath the sewer, or elevated above.

Going slow works or using a tunnel shield for 20m.

[jollyburger]

8th Avenue has a large interceptor as well that hooks into Highbury. It's a 2m unreinforced diameter pipe. It was tunneled so maybe 20-50m down?

[BaddieB]

Originally Posted by scottN

A cut and cover tunnel from broadway/alma to 8th avenue would have to cross the highbury interceptor, a 2.9m diameter sewer pipe underneath highbury street. I don't think that's going to work. It either has to be a deep bored tunnel underneath the sewer, or elevated above.

If it doesn't go deep, could it not be cut and cover still, just dug underneath? That pipe would still be a problem when boring anyways.

Anyways, I'm just shooting ideas for what could be cheaper than boring.

[MalcolmTucker]

Originally Posted by jollyburger

8th Avenue has a large interceptor as well that hooks into Highbury. It's a 2m unreinforced diameter pipe. It was tunneled so maybe 20-50m down?

Highly dependent on soil conditions, but the clearance needed is far less than you suppose. Could be as little as 2m.

[jollyburger]

Originally Posted by MalcolmTucker

Highly dependent on soil conditions, but the clearance needed is far less than you suppose. Could be as little as 2m.

I wonder if Metro Vancouver/COV want a tunnel (either bored or cut & cover) or elevated guideway to run over a sewer interceptor? I guess the talk of an alignment along 8th Avenue near Jericho means it's not that important?

[MalcolmTucker]

Originally Posted by jollyburger

I wonder if Metro Vancouver/COV want a tunnel (either bored or cut & cover) or elevated guideway to run over a sewer interceptor? I guess the talk of an alignment along 8th Avenue near Jericho means it's not that important?

There are plenty of services to work around. A major sewer is on Broadway itself for 7 blocks around MacDonald.

https://gis.metrovancouver.org/mvmaps/sewer



https://opendata.vancouver.ca/explor...561,-123.19641

[jollyburger]

Originally Posted by MalcolmTucker

There are plenty of services to work around. A major sewer is on Broadway itself for 7 blocks around MacDonald.

https://gis.metrovancouver.org/mvmaps/sewer

https://opendata.vancouver.ca/explor...561,-123.19641

I know you can hang pipes etc during construction and build under it but I meant for future access. I guess with a tunneled interceptor you are never going in to service it?

[MalcolmTucker]

Originally Posted by jollyburger

I know you can hang pipes etc during construction and build under it but I meant for future access. I guess with a tunneled interceptor you are never going in to service it?

From the outside, pretty much. From the inside you can re-line. Once it reaches a risk point, you replace it.

[VancouverOfTheFuture]

the only place this thing might go cut & cover/not bored tunnel is once it hits the endowment lands. otherwise, it'll be bored.

[scottN]

Originally Posted by BaddieB

If it doesn't go deep, could it not be cut and cover still, just dug underneath? That pipe would still be a problem when boring anyways.

Anyways, I'm just shooting ideas for what could be cheaper than boring.

I did a little more investigation. The highbury interceptor is downhill from 4th avenue (8m above sea level) to Iona Island. Ground level at broadway / highbury is 20m above sea level, so that means the top of the sewer pipe is at least 12m underground at that point. Therefore I think that a cut and cover tunnel would actually go over it, not under it.