The Toronto subway system has been rapidly expanding over the last few years and an estimated 28.5 billion Canadian dollars (19.3 billion euros) will be invested in the next 10 years. Metrolinx and Infrastructure Ontario, two provincial government agencies, are leading the project to deliver the Toronto subway expansion for the Ontario Ministry of Transportation.
A key part of the expansion is the extension of the Eglinton Crosstown Line, the first section of which is nearing completion. Metrolinx and Infrastructure Ontario launched the tender for the Western Extension tunnelling works, which is for 6.3 km of tunnels for the 9.2 km extension, forming the backbone of the expansion. Plans are also being explored to extend the line even further, to Pearson International Airport. The tunnels will be built in advance and the stations added in a later phase to reduce construction times. The construction timeline for the tunnels is 4.6 years, with completion in 2025.
The West Extension will be a twin tunnel bored with two EPB type TBMs, each tube with an internal diameter of 5.75 m. The tunnel will run from the future Mount Dennis station to Renforth Drive, through urban areas where the water table is at surface level and rocky terrain alternates with soils. One of the project’s challenges is the presence of two sections, each about half a kilometer long, with a mixed face of soil and rock, which complicates TBM operation. The scope of work also includes launch and extraction shafts, a short cut-and-cover section and the headwalls for emergency exit buildings and stations.
“Large tunnel construction experience applied to the improvement of urban transportation in Toronto”
The West End Connectors team was awarded the contract and includes the contractors Dragados, Aecon and Ghella, who will carry out construction with a construction budget of 720 million Canadian dollars (485 million euros). TYPSA and the Canadian engineering firm EXP form the design team, which previously took part in the tender process.
TYPSA is in charge of design and certification during the main tunnel construction activities:
- TBM tunnel, including cross-passages and the design of the TBMs
- Precast tunnel lining
- Comprehensive ground movement assessment
- BIM, LOD level 350
and is also participating in geotechnical and structural engineering activities.
TYPSA is working on the design out of its offices in Canada, Spain, USA, UAE and Arabia.