TBM excavation complete for Seymour-Capilano
Nov 2010
Robbins News Release
- Excavation of the treated water tunnel for the twin Seymour-Capilano water conveyance project in Vancouver has hit its mark. The 3.8m diameter Robbins TBM punched through into the parallel raw water tunnel at the end of its 7.1km long drive. The twin TBM in the parallel raw water tunnel came to its end point in mid-October.
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Crew celebrations after a long drive
- Completion of the two drives is credited to the Seymour-Cap Partnership, a joint venture of Frontier-Kemper Constructors ULC, Aecon Constructors, and JF Shea. The JV operated the TBMs through the last half of the 7.1km long drives after termination of the initial construction contract in May 2008. Using all the same equipment and logistics established and mobilised by the original contractor, the Seymour-Cap Parnership complete the last 3.3km of the treated water tunnel (TWT) and 3km of the raw water tunnel (RWT), bringing both to a location in Capilano where a raise bore will be complete to connect the tunnels to surface infrastructure that will direct raw water from the Capilano reservoir to the treatment plant at the Seymour end of the TBM drives, and treated water back to Capilano for distribution to customers.
- Having broken into the Capilano chamber area from where the raise bore will be executed, the TWT TBM will be moved back and prepared for dismantling. The TBM in the RWT drove on beyond the end point where its trailing gear was separated from the machine and backed up to the entrance of the Capilano chamber.
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Breakthrough after 30 months of excavation
- From there it was used for power delivery, pumping of water ingress and mucking of the chamber excavation on the trailing gear conveyors back to the muck skips. The trailing gear systems will be used also for mucking out the raise bore excavation. Muck trains carry excavated rock back to the working shaft at Seymour for disposal.
- The Seymour-Cap Partnership resumed TBM excavation of the twin tunnels in mid-2009 and set against warnings of unstable rock conditions ahead, both tunnels are reported to be complete earlier than expected.
- The twin 7.1km (4.5 mile) long tunnels, for project owner Metro Vancouver, were driven in challenging granitic metavolcanic rock, with cover of up to 600m (1,97ft). The project's second contractor, the Seymour Cap Partnership (SCP), managed faulted and shear zones. Rock support varies from none in good ground (Class I), to rock bolts, wire mesh, and channel straps, as well as steel sets every 760mm (30in) in Class V poor rock.
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Support applied as needed
- "We are quite pleased with the breakthrough. The success of this project can be attributed to having an excellent crew of knowledgeable people, good pre-planning of the work and very good TBMs," said Frontier-Kemper Project Manager, Serge Moalli. Since SCP's re-start of the two TBMs in July and August 2009, the machines have achieved rates of up to 29m (95ft) per day.
- The second Robbins TBM holed through at an angle into the other tunnel, where a chamber will now be built to conduct raise drilling of the 270m (885ft) deep Capilano shaft. Frontier-Kemper estimates that this work, combined with final shotcrete and steel lining in the tunnels, will take about two years.
- The completion of the project will mark one of only several examples of TBM tunneling in British Columbia. "I think we've proven here that you can tunnel through the hard granitic rock of British Columbia, even with all its quirks and stress releases. We've shown that this is an effective alternative to drill and blast," said Moalli.
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Vancouver's twin tunnels reach target - TunnelTalk, Oct 2010
Vancouver's twin tunnels about 75% complete - TunnelTalk, May 2010
Twin tunnel restart comes at a high price - TunnelTalk, April 2009
Vancouver's twin tunnels contract terminated - TunnelTalk, May 2008
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