Confederation Line (Stage 1) | In Service 1.0

[Richard Eade]

Originally Posted by rocketphish

Sinkhole filled, traffic may return to normal Monday

By Tom Spears, OTTAWA CITIZEN February 22, 2014 1:12 PM

...

There has been no sinkhole under Laurier itself.

...
http://www.ottawacitizen.com/news/Sinkhole+filled+traffic+return+normal+Monday/9539722/story.html

Well I should hope that there hasn't been a sinkhole under Laurier; the tunnel doesn't extend that far - yet. I expect that the overburden under Laurier consists of the same fine material that they just experienced; and fine material is not held up by the wide spacing of their spile 'umbrella'. Me thinks that there is some re-thinking needed for at least the next 20 metres.

[eemy]

I'm not sure that a TBM would have handled it any better.

[J.OT13]

No but I think cut-and-cover might have been the best method for the area up to Laurier considering the bad soil conditions of Sandy Hill.

[Catenary]

Originally Posted by J.OT13

No but I think cut-and-cover might have been the best method for the area up to Laurier considering the bad soil conditions of Sandy Hill.

I agree, at least up to the intersection at Laurier, since it would not have negatively impacted traffic. Then there would only have been a short distance under the intersection before the bedrock.

It seems like a minor setback overall though, once the lining is in it doesn't make a difference.

[lrt's friend]

a cut and cover approach would have required further rerouting of the Transitway and further disruption to the traffic in the area in general. In other words, for a time, Laurier Avenue would have to be closed.

[Radster]

Originally Posted by lrt's friend

a cut and cover approach would have required further rerouting of the Transitway and further disruption to the traffic in the area in general. In other words, for a time, Laurier Avenue would have to be closed.

Minor inconvenience for a few months, really. Cut and cover happens in some very busy traffic-congested cities - ie. Metro Line 2 in Warsaw. They just deal with it, reroute traffic etc. I too agree they should have done cut and cover for the first 40 metres or so until the bedrock portion.

[McC]

they might still have to.

[lrt's friend]

Originally Posted by Radster

Minor inconvenience for a few months, really. Cut and cover happens in some very busy traffic-congested cities - ie. Metro Line 2 in Warsaw. They just deal with it, reroute traffic etc. I too agree they should have done cut and cover for the first 40 metres or so until the bedrock portion.

Regardless, there needs to be a plan on what to do with all the buses. You just can't shut down the Transitway for a cut and cover operation that might take a week, a month, 3 months, whatever. We had a plan. It may no longer work.

[Kitchissippi]

The Laurier crossing could be built like a bridge or the tunnel sections could be brought in precast sections. at most it would just be lane reductions. And while the ground is open, they might as well build provisions for a Laurier Station

[Dado]

In the strictest sense they wouldn't even need to build the full tunnel (i.e. roof and walls) from the cut; just dig down far enough to lay down a large expanse of concrete and cover it back up again. The tunnelling equipment would then be able to proceed to dig the tunnel beneath the concrete pad, followed-up by the usual shotcreting to build the tunnel dome.

At Laurier this could have been done months ago, long before the tunnelling equipment got anywhere near Laurier.

[Uhuniau]

Originally Posted by Kitchissippi

The Laurier crossing could be built like a bridge or the tunnel sections could be brought in precast sections. at most it would just be lane reductions. And while the ground is open, they might as well build provisions for a Laurier Station

YES!

It's kinda ridiculous that there isn't one from the start.

[J.OT13]

Originally Posted by lrt's friend

Regardless, there needs to be a plan on what to do with all the buses. You just can't shut down the Transitway for a cut and cover operation that might take a week, a month, 3 months, whatever. We had a plan. It may no longer work.

A good part of the Waller Transitway, Nicholas to Laurier has been closed from the start. They could have cut-and-covered up to Laurier, only a few meters from bedrocks and they wouldn't have had to close Laurier or the north part of the Waller Transitway. They couldalso have made the part of Nicholas that "hugs" the Desmarais Building a two way Transitway until that part of the tunnel is completed if they opted to cut-and-cover to all the way to bedrock. Minor effect on traffic, none on the Transitway.

[rocketphish]

Cause of sinkhole remains elusive as work continues

By Joanne Chianello, OTTAWA CITIZEN March 3, 2014 6:19 PM

OTTAWA — More than a week after a three-by-three metre sinkhole opened up near the intersection of Waller Street and Laurier Avenue, the city is no closer to having any answers as to why the road collapsed.

The only explanation anyone has suggested for the sinkhole was that it was somehow caused by the tunnelling under Waller for the city’s light-rail project, but that has not been officially confirmed. Nor are there any answers as to whether it’s safe for Rideau Transit Group — the consortium building the LRT system — to continue to dig underground.

In an email to members of council Monday, city deputy manager Nancy Schepers reported that “RTG is continuing with their detailed investigation into the cause of the collapse and their assessment of the site in preparation for resuming tunnelling operations.”

On Tuesday, wrote Schepers, RTG plans to drill boreholes along the tunnel alignment “to increase confidence and confirm soil conditions.” The excavation on the eastern end of the tunnel is 15 to 20 metres from hitting the hard bedrock that’s under most of downtown Ottawa, where the digging is expected to get simpler. The investigation will result in “minor” traffic delays overnight for about a week.

RTG will also continue “investigative drilling” in the tunnel itself.

Schepers reported that work to permanently connect to the main sewer should be finished by this Friday.

More definitive answers are expected later this week.

“The city anticipates receiving both the results of RTG’s investigation and their plan to recommence tunnelling operations later this week,” Schepers wrote in her email.

[email protected]

twitter.com/jchianello
© Copyright (c) The Ottawa Citizen

http://www.ottawacitizen.com/news/Cause+sinkhole+remains+elusive+work+continues/9573286/story.html

[rocketphish]

Construction Summary
Week of March 2

Central Segment

TUNNEL

West Portal (Jawbreaker) (approximately 300 metres)

• Mining as well as shotcreting and reinforcing the tunnel is ongoing.
• Tunneling advances east under Queen Street, just past Bay Street.

Roadheader mining advances at west portal


Central Shaft (Chewrocka) (approximately 23 metres)

• Shotcreting and tunnel reinforcements continue as mining advances in the running tunnel.
• The gantry crane continues removing debris.
• Equipment and dewatering system installation continues this week.

Gantry crane testing at the central shaft


East Portal (Crocodile Rouge)

Tunneling operations were suspended at the East Portal due to a roadway collapse on Waller Street. The cause is currently being investigated.

For weekly updates on tunnel excavation progress please visit the Roadheader page.

East Segment

Maintenance and Storage Facility (MSF)

Some site activities such as equipment mobilization and snow clearing are scheduled to begin as early as mid-March. Construction on the MSF building is scheduled to begin this spring.

CIVIC WORKS

Highway 417 Widening and Structure Rehabilitation

Roadworks

• Boring operations continue east of Vanier Parkway.

Signage

• Overnight installation of the overhead variable message signs (at Parkdale Avenue, Walkley Road and Blair Road), which will provide updated information to motorists, have been completed. OPP was onsite to assist during full highway closure.
• Underground installation of cables and pads to power the three message signs continues.

Overnight installation of VMS at Parkdale


Structures

Widening, reconstruction and rehabilitation of various bridge structures is progressing as planned along the highway

Hurdman Bridge

• Installation support points and erection of girders continue this week.
• Installation of deck soffit formwork* occurs.
• Pouring of abutment extensions continues.

Overnight girder installation at Hurdman Bridge


Girder installation at Hurdman Bridge


St. Laurent Boulevard Overpass

• Widening and rehabilitation continues with grade work all week.

Vanier Parkway Overpass – work progresses in preparation of the rapid bridge replacement.

• Steel work and removals are progressing as planned.
• Preparatory work for the rapid bridge replacement is ongoing in the staging area.

Belfast Road Underpass – work progresses in preparation of the rapid bridge replacement.

• Piling activities are ongoing to support temporary structure.
• Refacing, pouring and concrete repairs on the north and south abutments continue.

Lees Avenue Underpass – work progresses in preparation of the rapid bridge replacement.

• Temporary foundation pouring is ongoing.
• Installation of rebar on retaining walls and of the metal protective system continue.

Pouring of temporary foundation at Lees Avenue


Notes:

*Formwork refers to a permanent mold in which concrete is poured.

http://www.confederationline.ca/#target2988

[c_speed3108]

"dewatering system"

[J.OT13]

Unanticipated soil conditions? Really? REALLY?

March 11, 2014
Update on Road Collapse on Waller Street

RTG has informed the City that the results of their root cause investigation and analysis have confirmed that the cause of the roadway collapse was due to unanticipated soil conditions.

Investigative work to inform RTG’s plan for resuming tunnelling operations within the tunnel continues.

The following work has been completed:
•The reconnection of the storm and sanitary sewer infrastructure work is now complete;
•Additional borehole investigations were completed in the area; and
•Full access to 50 Laurier has been restored.

A final update will be provided once the City has reviewed RTG’s plan for tunnel commencement at the East Portal.

http://www.confederationline.ca/en

[ortelius]

Any chance that tunneling can't be done for that area before they reach the better soil?
If not, what are the options?

[J.OT13]

Originally Posted by ortelius

Any chance that tunneling can't be done for that area before they reach the better soil?
If not, what are the options?

I assume that the heavy rain on the Thursday night likely played a major role in the collapse, so it's likely not 100% soil conditions, but to answer your question, there is an off chance that they may decide against continuing the mining technique in that area.

Remember that they are only about 20 meters from bedrock, so worst case scenario, if the soil conditions are too sketchy to continue with the mining method, they might have to close Laurier for a month or two to cut and cover that small gap.

After this, it should be smooth sailing; the rest of the tunnel will be dug deep underground in solid bedrock. The only other place where they might encounter a problem is around O'Connor where there's apparently a fault line. We also have the canal, but that area is where the tunnel will be at its deepest to avoid any conflict with the UNESCO site and a major sewer line.

[Badlands]

Originally Posted by J.OT13

Unanticipated soil conditions? Really? REALLY?

http://www.confederationline.ca/en

Really? REALLY? LOL. I guess only you and Ken Gray can see underground. Goodness, we are all going to die.

It is a minor setback in the grand scheme of things. Bring on Phase 2.

[hwy418]

Originally Posted by Badlands

Really? REALLY? LOL. I guess only you and Ken Gray can see underground. Goodness, we are all going to die.

It is a minor setback in the grand scheme of things. Bring on Phase 2.

Exactly my thoughts - having a project of this magnitude excute without any issues or setbacks would be unheard of. This sinkhole thing could have been worse - yes, but it wasn't so lets move on.