Cut and cover tunneling is one of the oldest methods of constructing a tunnel. The basic concept involves digging a trench, constructing the tunnel walls and roof, and then backfilling it at the surface.
Each cut and cover tunnel section will be constructed using the following steps:
Step 1 – Prepare: Relocate utilities, walkways, and traffic as needed.
Step 3 – Cut: Excavate the tunnel trench.
Step 5 – Cover: Backfill and reinstate surface.
Step 2 – Support: Support walls are installed for reinforcement during tunnel excavation.
Step 4 – Construct: Tunnel foundation, walls, and roof are constructed using steel struts and concrete walls.
Where and when will tunnel construction take place?
The 3-kilometre Parkway Tunnel will run between Dominion Station and Lincoln Fields Station underneath the Sir John A. Macdonald (SJAM) Parkway and Byron Linear Park.
The 270-meter Connaught Tunnel will travel from Connaught Park, underneath Connaught Avenue, to Queensview Station.
While some areas such as Connaught and the SJAM corridor may see cut and cover construction begin in fall 2020 with support of excavation, the overall tunnel construction will be in full swing across all segments by 2021. Tunnel construction will progress from one project area to another as each step is completed.
By 2023, the majority of the underground guideway will be complete, and crews will focus on installation of the track, and the electrical systems as well as building the New Orchard and Cleary Stations. These operations generally do not require as much traffic disruption as the sites become more contained for station construction.
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