Tunneling to commence in Toronto
May 2011
Paula Wallis, TunnelTalk
- Four Caterpillar (formerly LOVAT) EPBMs are ready for launch on Toronto's 8.6km (5.4 mile) Toronto-York Spadina Subway Extension. The machines are assembled and are awaiting completion of the launch shafts.
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One of four Lovat EPBMs at Sheppard West Launch Shaft
- "We have had quite a bit of rain in April, which delayed the pouring of the mudslabs in the two launch shafts," said Andy Bertolo, Chief Project Manager for Toronto Transit Commission. "We expect they will be finished shortly, ready for a launch in June."
- Aecon holds the Can$279 million contract for the tunnel drives from the current terminus at Downsview Station to a new Finch West Station and the cut-and-cover construction of the Sheppard West Station. Aecon's tunneling partners, McNally Construction and Kiewit Construction, will excavate the twin 2.6km (1.7 mile) tunnels using two of the four machines.
- The EPBMs will be launched, one after the other, from a shaft at Sheppard West Station, and will excavate their respective drives simultaneously to the Downsview Station, then re-launched to complete their drives north to the reception shaft at the Finch West Station (Fig 1).
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Fig 1. Spadina Subway Extension
- The second Can$404.5 million tunneling contract is held by OHL & FCC and includes the drives from Finch West Station to Vaughan Corporate Centre Station plus cut-and-cover construction of the Highway 407 Station. The contractor will excavate the 6km (3.7 mile) of tunnels using the remaining two machines, which will be launched consecutively from a shaft at the Steeles West Station for their drive south to the Finch West Shaft, then re-launched for the drives north to the Vaughan Corporate Station (Fig 1).
- All four machines, procured by the Toronto Transit Commission (TTC) to expedite the construction schedule, have been passed to the contractors. Along with the EPBMs, two representatives from Caterpillar are assigned to each contractor for the duration of the excavation. "They will attend to the TBMs on a daily basis to make sure the machines are performing as specified," said Bertolo. "Since the Commission owns the machines, if they don't perform, the contractor can claim against us. So to have the Caterpillar representatives on site for a little over a year to care for the machines, is well worth the added investment." At the end of the project the TBMs will be returned to the Commission for possible use on further projects.
- The alignment is almost entirely below the groundwater table with sections of extensive hydrostatic pressure, however most of the alignment is in relatively shallow ground with a maximum depth of about 18m (60ft).
- The Toronto Transit Commission also procured the precast concrete segmental liners from Armtec. The segments are being produced at a plant in Woodstock about 70km (43 miles) from the project and at a plant in Brampton about 50km (31 miles) north of the site. "About 250 segments have already been delivered to the Sheppard West Station launch shaft," said Bertolo, with delivery to begin at the northerly Steeles West Station launch site next week.
- Hatch Mott MacDonald (HMM) was awarded design of the twin tunnels in November of 2008. HMM/Delcan/MMM Group JV holds the construction management contract for the Can$2.63 billion extension.
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Fig 2. Toronto Transit plan
- Aside from the tunneling contacts there are four separate cut-and-cover station contracts. Finch West Station is on track to be awarded soon to Bondfield Construction, a Toronto based company, which submitted the lowest bid of Can$127 million for the contract, said Bertolo. Vaughan Corporate Station is currently out to tender and it will be followed by Steeles West Station by the end of the month (May 2011) and York University Station in June or July. Of the four stations, York University will pose the greatest challenge, as it is located in the University Common, in very tight quarters and adjoining other structures. It will also require extensive ground-improvement measures.
- The Spadina Line extension is one of several transit expansion projects planned by the City of Toronto to bring public rail transport to a wider service area. Planned projects include the 25km Eglinton Crosstown LRT project, which is moving into construction, and the 6.8km Yonge Subway Extension, both of which include extensive sections of bored running tunnels and underground stations. The Spadina Line Extension, as the first of these projects, is expected to open late 2015.
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Spadina extension awarded in Toronto - TunnelTalk, Nov 2010
Toronto Metro gears up for tender - TunnelTalk, Sep 2009
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