Viau

• The site of the future métro station has already been partitioned off, and the microblasting will take place within the construction zone.
• Safety instructions will be posted around the site.
• Blasting mats will be installed over the rock to contain the micro-blasts.
• No explosives will be stored on site.
• We’ve hired a specialized firm to monitor the vibrations and ensure compliance with the City of Montréal’s standards.

1. 12 whistle or siren sounds
2. 30-second wait
3. Microblast
4. 1 long whistle or siren sound
5. End of microblasting

The controlled microblasting excavation work will start in July 2025, and will continue through fall 2025. There will be an average of three microblasts per week.

For safety reasons, during each microblasting operation, a restricted area around the site will be temporarily closed to traffic, for a period of about 10 minutes. Employees will be present to coordinate this maneuver.

In the coming months, we’ll be starting excavation work to make way for new infrastructure for the Blue line project.

The excavation method will vary depending on the type of work being done. The surface excavation work will involve controlled microblasting, whereas most of the excavation for the underground tunnel will be done using a tunnel boring machine, or TBM. At both types of worksites, there will also be some mechanical excavation. The vibrations produced by the different excavation methods will be measured on an ongoing basis using seismographs. These devices will be installed at various points throughout the excavation zones and will be used to continuously monitor the vibration levels and make sure they fall within legal limits.

Essential preventive measures

To prepare for upcoming excavation work, the STM has tasked ABS with inspecting buildings that meet at least one of the following criteria:

• Located within 75 metres of any surface-level excavation work
• Located within 30 metres of the tunnel axis

The inspections will serve to compile an inventory of the structures surrounding the worksites for the Blue line project. The findings of the inspections will also be used to establish the maximum vibration levels for each site. Although these inspections are a precautionary measure, they are essential in the unlikely event that the work causes any damage.

As a further precaution, any building within 100 metres of a worksite where there will be microblasting will receive a carbon monoxide detector a few weeks before the excavation work starts.

Each building inspection lasts approximately 15 to 30 minutes. Photos are taken of the building interior and exterior. The photos are mostly close-ups of the foundations, walls, ceilings, and floors and serve to document the building’s condition prior to the start of the excavation work.

The pre-construction inspection is a common precautionary measure for major construction sites. It protects you in the unlikely event that your property suffers any damage during work on the Blue line project.

Controlled microblasting is used on several major STM worksites, depending on the type of rock to be excavated. To learn more, watch the video in the FAQ section of our Blue line project page.

In the fall of 2024 and 2025, urban forestry work will take place around the Blue line project worksites. Trees that interfere with the construction sites will be protected, replanted, or cut down. Our team of forest engineers, landscape architects, urban planners, and sustainable development experts has carefully planned these interventions to preserve as many trees as possible.

The goal is to replant the trees wherever possible. Soverdi, the not-for-profit organization overseeing the replanting process, will monitor and care for the trees after they are transplanted to ensure their survival. Trees that can’t be replanted due to their size or condition will be recycled into wood chips, firewood or compost depending on the quality of the wood. The health and species of the trees will also help determine which ones need to be cut down, based on whether they are diseased, subject to borer infestations, or invasive, among other factors.

Ultimately, Blue line project sites will be revegetated and several hundred new trees planted, for a stronger, healthier canopy. For every tree replanted or cut down, we will plant more than two in their place.

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These organizations are collaborating on the project’s phasing strategy so that all the work lines up to keep local travel running smoothly and ensure good management of their investments. During the excavation, the City of Montréal and other stakeholders will take the opportunity to upgrade underground infrastructure.

The preparatory work involved relocating urban public utilities, giving us free rein to begin the massive excavation that will be needed to build the new métro station. The utilities that needed to be relocated include water pipes, sewers, and underground conduits and cabling.

We are finalizing the overall project schedule based on multiple factors. We will keep you informed as the project progresses and let you know when the work will begin.

Projects like the Viau area preparatory work need to be planned months in advance. Together, our experienced technicians, engineers and project managers pool their knowledge of a variety of disciplines, including civil engineering, structure, electricity, building mechanics, geotechnics, traffic maintenance and sustainable development.

Our design, project management and follow-up teams are putting their expertise to good use in the east end of the city, and all this is just the beginning!