Michel-Ange auxiliary building

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.

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.

An auxiliary building is a service building, closed to the public and located between two métro stations, that houses a variety of mechanical and electrical equipment needed for métro operations. This includes ventilation equipment, power supply infrastructure and pumps to remove runoff water. There are currently hundreds of these buildings in the métro network.