If Evergreen Line tunnel boring is complete, why more delays? (VIDEO)

Dec 20 2017, 2:46 am

Residents in Metro Vancouver will have to wait even longer before they are able to add the Evergreen extension of SkyTrain’s Millennium Line to their list of travel options.

Earlier today just before 9 a.m., the tunnel boring machine named Alice made its breakthrough at the south portal located at the intersection of Clarke Road and Kemsley Avenue. Loud cheers in Italian discourse could be heard from down below in the pit when the tunnel boring crew of approximately 200 people, from Italian boring company SELI, began celebrating the much-awaited completion.

This was SELI’s second tunnel boring project in Metro Vancouver. It also built the twin tunnels for the Canada Line under False Creek and downtown Vancouver, without issue.

Evergreen Line tunnel boring machine breakthroughIt’s a breakthrough! This morning, the 10-metre diameter tunnel boring machine for the #SkyTrain Evergreen Line saw daylight, effectively ending its journey.

Posted by Vancity Buzz on Friday, November 27, 2015


But up above in the observation area, a delegation of media were prodding Peter Fassbender, the Minister of TransLink, why the opening date has been delayed again, for the second time, and whether taxpayers will be on the hook for extra costs. Initially, completion was scheduled for summer 2016, then it was pushed to fall 2016 and now early 2017.

Tunnelling began in March 2014, and as work progressed crews encountered issues due to the loose glacial till deposits found along the 2.2-kilometre-long tunnel route, which has a maximum depth of more than 50 metres – about 17 storeys below the surface.

Because of the additional machine drilling head maintenance required due to the challenging soil conditions, the machine was stopped over extensive periods. This in turn caused a number of small surface sinkholes to form directly where the machine had stopped.

In the end, it took 20 months – three times longer than originally anticipated – to finish the bored tunnel segment. It was initially slated for completion within a 200 day timeline.

“When you do something as unique as this project, you have to expect there may be things as they are doing the tunnelling that they didn’t expect,” Fassbender said. “So I think success is the fact that we are moving ahead, we see the tunnel now and the rest of the project… There will always be challenges but they’ve overcome it.”

Currently, the overall project is 75 per cent complete, with stations between 80 per cent and 99 per cent complete. The elevated and at-grade guideways were completed earlier this spring, and test trains began rolling on the southern portions of the extension in July.

While tunnel boring is complete, much more work still needs to be done over the next 12 months before test trains can run through the 10-metre-diameter tunnel to Lafarge Lake-Douglas Station in fall 2016. Aside from removing the tunnel boring equipment, and before tracks and other systems can be installed, crews will be creating a flat surface for trains to run on and dividing the tunnel with a wall to separate the trains traveling in opposite directions.

The project will cost $1.43 billion, which is funded by the federal government with $425 million, the provincial government with $586 million, and TransLink with the remaining balance although Lincoln Station is partially funded by the owners of Coquitlam Centre Mall through a public-private partnership.

And if there are any overruns, taxpayers will not be on the hook. SNC-Lavalin, the contractor of the project, is responsible for picking up any construction cost overruns incurred as stipulated in an agreement.

As Fassbender noted, infrastructure projects of such a significant scope often run into unforeseen issues, and the tunnel boring process is particularly risk-prone. There have been two other recent local examples where tunnel boring did not go exactly as planned.

Metro Vancouver Regional District’s Seymour-Capilano Water Filtration Project was completed this past spring after more than a decade of construction and engineering problems. The $820-million project spanned the length of Grouse Mountain with two side-by-side 7.1-kilometre-long tunnels, each with a diameter of 3.8 metres through hard granite rock at depths between 160 and 640 metres.

The original contractor halted boring work when it deemed that the project’s risk was too great and could not overcome engineering issues it encountered. Eventually, the contractor was dismissed for stopping work and a new contractor was hired to complete the boring work using the same engineering designs and tunnel boring machines.

The project went $170 million over the original budget, and a litigation process is still underway between the original contractor and the regional district.

More recently, Seattle has been undergoing the Alaskan Way Viaduct replacement project, a US$3.1-billion project to demolish the existing viaduct route with a 3.2-kilometre-long, 4-lane underground replacement. Construction centres around the usage of Bertha, the world’s largest tunnel boring machine – a diameter of 17.4 metres.

Bertha began boring on July 30, 2013. A little more than three months later, the machine hit a major snag: It drilled into a 20-centimetre-diameter, 119-foot-long steel pipe from a soil test drilling project nearly a decade earlier.

The machine also had to be stopped because of overheating issues and a break in the seal system.

At this point, the necessary repairs to Bertha were too extensive to be fixed underground. The repairs required crews to excavate a 37-metre deep pit to lift the machine up to the surface. This began in December 2014 and the machine was lifted up at the end of March 2015.

Over the course of much of the year, crews have been repairing Bertha and performing thorough tests. Tunnel boring for the project is expected to resume before Christmas.

To date, Bertha has only completed 330 metres of 2,830 metres of tunnel length, barely 12 per cent of the entire route in over two years. In the meantime, a lawsuit is underway between the contractor and insurers who are trying to avoid a $143 million compensation for the repair costs.

Lessons have been learned with these three projects; local officials and planners are now exercising the utmost of their due diligence for the proposed underground extension of the Millennium Line under Broadway – a $1.9-billion, 5.1-kilometre-long extension with six stations from the existing VCC-Clark Station to the intersection of Arbutus Street and Broadway.

Since late-summer, geotechnical drilling crews contracted by TransLink and the City of Vancouver have been performing soil test drills along much of the subway’s route on Broadway. At least a dozen tests, each at a different location, have been performed to assess the soil composition and geotechnical stability of the area. The future extension will run through buried streams and glacial deposits, such as large boulders.

It could have been much worse with the Evergreen Line, but with the completion of tunnel boring the project has now conquered its most challenging obstacles.

When trains begin operate on the Evergreen extension, it will bring the length of SkyTrain to 79 kilometres. In fact, Metro Vancouver’s regional rapid transit rail network will claim the title of Canada’s longest rapid transit rail system from Toronto and the title of the world’s longest fully automated rapid transit system from Dubai Metro.

“Like everything, I think we have to take the long-term view,” Fassbender added. “This project is going to deliver transportation to the region. It is an amazing project, it has had its challenges, but I know it will serve the people of this region very well.”

For transit users, the Evergreen Line provides a seamless one-train ride from Vancouver to Coquitlam. It allow transit users to travel from VCC-Clark to Lafarge Lake-Douglas stations in about 35 minutes and Lougheed Town Centre to Lafarge Lake-Douglas stations in 15 minutes.

Planners anticipate the Evergreen Line will carry 50,000 passengers per day upon opening, growing to 70,000 per day by 2021.

DH Vancouver StaffDH Vancouver Staff

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