Crews on Scarborough Subway Extension prepare for excavation

Construction at the northeast corner of Sheppard Avenue East and McCowan Road is in full ‘drill mode’ as crews make progress on expanding the TTC’s Line 2 subway service almost eight kilometres further into Scarborough. Here’s where those crews are at, and where they’re going.

The project team responsible for the Scarborough Subway Extension is ramping up efforts to prepare for excavation.

The extension, which broke ground in June, will provide seamless, reliable transit to key areas in Scarborough and service approximately 105,000 riders each day.

Image shows the map.
Here’s the Scarborough Subway Extension map (Metrolinx photo)

Crews are preparing a launch shaft at the northeast corner of Sheppard and McCowan. This large excavation will be used to lower the tunnel boring machine into the ground next year.

The work of ‘secant piles’

“We’ve completed drilling over 200 secant piles so far as part of our preparations to begin excavation,” said Uhland Konrad, Design and Build director for Strabag, the contractor in charge of tunnelling underground for the project.

Those secant piles – you can find out more details in another story at the end of this piece – are reinforced concrete columns used to create a water-tight barrier around the perimeter of the area that will be excavated for the launch shaft. 

Image shows a large drill.
Here’s secant pile drilling underway at the launch shaft on the northeast corner of Sheppard and McCowan (Metrolinx photo)

Strabag was selected through procurement to construct the tunnel for the Scarborough Subway Extension Project. They are a global leader in tunnelling technologies and have built complex transportation infrastructure in more than 60 countries. That expertise will be well used on this project, which will see the construction of a launch shaft that is approximately 80 metres long, 30 metres wide and 25 metres deep.

“We are staying aware of not only what is happening within the construction site, but also around the area.”

Uhland Konrad, Design and Build director for Strabag

“Tunnelling requires extensive experience,” Konrad said. “We understand how important it is for the public to have access to transit in this part of the city and we are working hard to complete the project as quickly and safely as possible.”

Sheppard and McCowan is a busy intersection and the safety of crews working inside the construction site as well as those walking outside is a priority for all those involved in the project.

Safety is paramount

“Safety is a major priority for us and our partners at Metrolinx,” Konrad explained. “We are staying aware of not only what is happening within the construction site, but also around the area. People walk past the site often, so we have safety checks at the gates to make sure everyone is safe.”

Metrolinx and Strabag have also installed safety signage around the site, reminding people to be aware of their surroundings as they move past.

Image shows a wall separating the work site from a sidewalk.
Safety signage installed around the launch shaft site (Metrolinx photo)

“Having the construction completed as quickly and safely as possible is important for everyone involved,” Konrad said.

Being a good neighbour to the local community is very important and Strabag has already put measures in place to reduce the impacts of noise and vibration from construction at the launch shaft site.

Noise and vibration measures

“Noise and vibration monitoring equipment have been installed on site and in different locations in the area to keep a close eye and ear on construction activities,” Konrad explained. “We’ve also installed a movable noise wall that is used to reduce sound from construction activities on site, especially when work is being done in the evenings or on weekends.”

Image shows a wall.
Noise wall installed at the launch shaft site to reduce sound from construction (Metrolinx photo)

Dust can be another common problem at construction sites when it’s windy, so Strabag is using water trucks to spray the worksite nearly every hour to minimize impacts on the surrounding community.

Water sprayer being used to minimize dust at the launch shaft site (Metrolinx photo)

Once teams complete the excavation and prepare the tunnel launch shaft, the tunnel boring machine will arrive on site. Then, crews will lower it into the launch shaft where it will begin working its way south underneath McCowan Road.

Community notices about the ongoing construction taking place at Sheppard and McCowan will continue to be updated and sent out to residents and businesses in the surrounding area. Stay tuned for updates regarding upcoming virtual or in-person events to learn more about the project and share your feedback.

Residents, businesses and those just interested in the project can reach out with thoughts, questions or comments to Metrolinx’s community relations team through a 24/7 hotline at (416) 202-7900 or email at ScarboroughSubwayExtension@Metrolinx.com.

Want to know more about secant piling? Here’s a story with some good facts.