In Canada the outlook for tunnelling in the next five to ten years is quite good, and 2011 will be no exception. Toronto has a host of transportation projects on the books that will require tunnels, and cities like Montreal, Vancouver and Ontario have projects underway or in planning. At the same time, sewerage systems across Canada require upgrades or expansions, signaling an upcoming boom in trenchless work.
Don Brophy, senior vice president of Aecon’s infrastructure division, says the market is pretty brisk. “Transportation in Toronto has been behind for years now and they’re just trying to catch up.”
Toronto’s Transit Commission (TTC) awarded a CAD 279M (USD 274M) contract for the first leg of the 8.6km bored twin tunnels for the Toronto-York Spadina Subway Extension on 19 November.
Within this contract, a joint venture consisting of McNally Construction, Kiewit Construction, and Aecon Constructors will construct the 2.6km of twin-tunnel subway track from the north end of Downsview Station, through the new Sheppard West station, to the new Finch West station. The twin tunnels will cross underneath Allen Road, several commercial/industrial properties and Sheppard Avenue West. Brophy says construction will start in December, with tunnelling to start in March 2011.
Toronto-based Lovat had been awarded a CAN 58M (USD 56M) contract to build the four TBMs that will be used to build about 6.6km of the tunnel, so contractors could have a head start once the projects were awarded.
The second contract is expected to be tendered on 15 December. It will include twin-bore tunnels and NATM to construct a double ended pocket track housing structure where trains can be turned at peak time.
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By GlobalDataLooking down the road and into the next five years, in Toronto there will be 10km of twin tunnels for the Eglinton Crosstown Light Rail Transit (LRT), worth CAD 4.6bn (USD 4.5bn), and a small segment of tunnelling work needed for the Sheppard East LRT. Vancouver is planning its 11km Evergreen Line, of which 2.3km may be double-track tunnel.
Just as with transportation, water treatment and sewerage systems have also been left behind, says Brophy. “A lot of the old systems are starting to break down,” he explains. “We are finding that deep tunnels are the solution.” This is because they don’t cause as much of an obstruction to cities compared to open excavations, and saying that an increase in trenchless work is highly likely.
That’s very much reflected in the workload of the City of Edmonton, where the drainage services department operates their own tunnelling design and construction section. Their operation has been going for the past 50 years, but recently they’ve started to do their own trenchless work in place of open cut, says Ray Davies, the department’s general supervisor for open-cut. At the moment he has numerous projects going including pilot tube, pipe ram and pipe burst methods.
The city has also put a TBM to work tunnelling this fall for the 3.7km North Edmonton sanitary tunnel, and has several other tunnel projects lined up for the next five years. “We’ve had a pretty healthy budget and we’ve got a lot of work to do,” says Davies.
In addition to meeting its transportation needs, Vancouver is seeing tunneling projects for water and wastewater systems. Tunnelling finished in November on the final 3.1km of excavation for the Seymour Capilano twin tunnels, after a hiatus of more than a year due to a ground conditions dispute. The tunnel is part of a water filtration project for the city’s water authority, Metro Vancouver. Separately, the water authority hopes to start construction on its Port Mann Water Supply Tunnel, which will be driven under the Fraser River by TBM, in 2011.
Beyond transportation and sewers, there is also the potential for tunneling work on power plants planned from coast to coast—BC Hydro’s proposed Site C hydroelectric plant to the west, and the Lower Churchill project in Newfoundland, in the east.
A 13-person crew operated the Robbins TBMs 20 hours a day, 5 days a week, on the Seymour Capilano twin tunnels in Vancouver
