Shani Wallis, TunnelTalk

Montreal, Canada - a venue that attracted an engaged international element to Canada's focused and vibrant Tunneling Association (TAC) and its biennial national conference. Co-hosting an ITA ExCo meeting was a definite boost to the delegation, but so too was Canada's confirmed program of investment in underground infrastructure both now and into the coming decades.

Underground extensions of mass transit systems in Canada's major cities has international attention.
• In Vancouver, SNC Lavalin with SELI and other consortium members is the preferred partner to design, build and finance the city's Evergreen light rail extension with its 2km (1.24 miles) of 6m diameter twin tube underground alignment. This continues its Canada Line success in Vancouver which was built and operational in time for the Vancouver Winter Olympic Games in 2010;
• Edmonton is working on an LRT extension with a critical section aligned underground;
• Toronto will have eight TBMs working simultaneously on transit tunnels within the coming years and has an ambitious program of future transit tunneling to 2031, with the Obayashi/Kenny/Kenaidan/Technicore JV awarded the first contract for the Crosstown Eglinton LRT and the Aecon/McNally/Kiewit consortium and the OHL & FCC JV working on the two tunneling contracts for the Spadina Line extension with four (Lovat) Caterpillar owner-procured TBMs;
• Montreal is progressing planning and design of new metro lines to add to its vast underground environment and
• Ottawa is the current focus of interest with three proposals in evaluation for award of a contract to design, build, maintain and finance the Can$2.1 billion Ottawa Light Rail Transit (OLRT) project which includes 12.5km (7.8 miles) of LRT line with 3.2km (2 miles) of twin running tunnels and four underground stations.

TAC President Rick Staples (right) thanks keynote presenters (from left) In-Mo Lee, South Korea; Erik Eberhardt, Canada; and Jeff Petersen, USA

In his keynote about current and future tunneling projects across Canada, Erik Eberhardt also highlighted several new hydro projects that require extensive underground excavation and major civil works for development of underground mining operations in the country. Eberhardt also cited Canada's heritage of tunneling projects and emphasized that underground projects should not be viewed as extravagances but rather as investments in long-term national development.

Jeff Petersen of Kiewit continued the theme with a presentation about the state of the tunneling market in the United States, noting that the focus is shifting from the north east of the country to the west, with major projects in the New York area in the finishing phases, and activity starting up on metro lines in Los Angeles and San Francisco. Progress continues on the high speed rail program for California and preparations are under way for major tunneling investments for the Bay Delta Conservation Plan (BDCP) water transfer tunnel project in Northern California. For Petersen, he said there were four major focuses for the industry as a whole:
• Safety - "There are still too many accidents and injuries and some way still to go on establishing a culture of safety first to reduce the incidents and impacts of accidents, which includes increasing insurance premiums."
• Need for people - "Not only college graduates, to replace the aging management in the leading industry organizations and companies, but also in the non-college educated, highly skilled operatives and workers."
• Technology development - "To not only achieve higher productivity from our machines and systems, but also to improve the safety regime of the underground structures we build and improve the cost effectiveness of projects for our clients."
• More creative funding and financing of projects - "The demand is great, for both new underground structures and the rehabilitation of the existing assets. We need more sources of vital capital to fund these needs than those available at present."

In-Mo Lee, President of the ITA, and ahead of chairing the ITA ExCo meeting, gave a keynote on the development of the underground for the sustainability of modern cities and urban societies. He explained how much he and his family appreciated the underground environment of Montreal when he spent a professorial sabbatical in the city from his native Seoul, and how Korea as well as so many other countries are exploring underground options for all types of purposes including flood management, nuclear waste repositories and options to reserve the surface for optimizing the quality of life and confining more urban services to the underground environment.

Members of the TAC committee (from left) Rick Lovat, President Elect; Conference Technical Chair, Marc-Antoine Beaupré; Conference Chair, Andre Rancourt; President Rick Staples; Conference Treasurer Marco Quirion; and Social Chair, Mylène Sansoucy

In a technical session dedicated to hydropower projects, Werner Burger of Herrenknecht, Remo Grandori of SELI, and Lok Home of Robbins described the unpredictability of the geology in long hydro headrace drives and the need to act quickly and decisively to solve particular problems and critical situations.

Burger described the failsafe systems needed to ensure security of TBMs used to complete drives on steep inclines, including at times of power failure or when working through fault zones of poor rock conditions.

Grandori said he has never worked with "a reliable geological forecast. Unforeseen conditions and spectacular forces of nature must be anticipated on long drives under high overburdens and it is good crews and a good contractor that will get through zones of bad ground. The TBM is on stop and discounted in these conditions until rescued."

Home confirmed that the horizontal alignment change on the mega-TBM Niagara tunnel drive in Canada was taken quickly, "leaving the contractual issues to be settled later", and that it worked well. The whole issue, he said, was the relationship between the TBM and the required rock support, describing how the open space between the gauge cutters on the rotating cutterhead and the edge of the forward shield is a weakness of open-faced, rock TBM design, allowing loose material of fault zones to flow in in an uncontrolled way.

In reply to a discussion period question by TunnelTalk, all agreed with the reply by Home that more effort should be spent on investigating conditions ahead of the tunnel face rather than investing heavily on geological investigations from the surface ahead of awarding long hydro tunnels. "And the project's engineering geologist needs to be involved with these investigations ahead of the face to ensure that the appropriate support systems are designed in advance of progressing into anticipated geological conditions," said Home.

In another keynote presentation Felix Amberg of Switzerland explained the considerations and processes followed in preparing specifications for the four rock TBMs and the support required for majority excavation of the 57km long twin tunnels of the St Gotthard baseline railway tunnel under the Swiss Alps. Despite the best laid plans, Amberg confirmed several changes and modifications of the TBMs and the support methods to cope with more difficult geological conditions than anticipated and particularly excessive stress relaxation deformation and squeezing phenomena.

Ambitious public transit plan for Toronto over the next 30 years

In one of the soft ground tunneling presentations, Tarcisio Celestino of Brazil described how the application of a program of jet grouting to support a full face NATM excavation for a metro project in an urban area caused more settlement than the excavation itself. "The medicine was causing the disease," he said. "Open face NATM excavations in urban areas is proven as competitive, flexible and safe, but a holistic approach is required to achieve all three."

A presentation by Gerhard Urschitz of Strabag explored the pros and cons of owner-procured TBMs for different projects. As Director for the company's tunneling interests in North America, Urschitz is managing director of Strabag's contract for the 15km long Southeast Collector sewer contract in the York Region of the Toronto metropolitan area using four 3.6m diameter EPBMs and a precast concrete lining procured for the contract by the owner. Tunneling is yet to start on the contract, said Urschitz, who confirmed he would present the actualities of using the owner-procured TBMs and lining at a future conference.

Other papers explored the choice between drill+blast and TBMs; continuous face support for large diameter closed-face pressurized TBM systems; application of steel fibres in precast concrete pipes; risk reduction through prescriptive specifications; and introduction of the new Toronto-York Spadina Subway Extension project to the tunneling fraternity. A particular point made about the attraction of the market in Canada is the many contractors and groups applying for prequalification on projects and a select list of up to 11 being invited to present proposals.

As well as a well organized conference program, the event included a hall of exhibitors that included Caterpillar; Sandvik; Normet; Robbins; Munro Precast Concrete Products; Herrenknecht; GKM Consultants; Babendererde Engineers; Geotech Drilling; and Williams Formwork and Rockbolts. Also available for free distribution to delegates were copies of the 2011 TunnelTalk Annual Review publication, which were going like hotcakes.

As well as the ITA ExCo meeting, the Montreal event also hosted the 2012 TAC annual general meeting at which Rick Lovat was elected to take over presidency of the Canadian Association from current President Rick Staples of Delcan in January 2013, and Steve Skelhorn of McNally is elected Vice President. Lovat is also a member of the ITA Executive Committee.

The Montreal event highlighted the importance of regional meetings in maintaining the international vitality of the very specific, yet truly global, nature of the tunneling business and how Canada has contributed and continues to contribute to the advancement of the industry. Canada has held the presidency of the ITA in Professor Dan Eisenstein of Edmonton, Alberta from 1992 to 1995. Professor Eisenstein was a firm supporter of the tunneling industry worldwide and was remembered when he died in 2009 with a scholarship in his name. His daughter Alice was on hand in Montreal to present this year's scholarship to a young lady studying civil engineering at one of Canada's leading universities.

Canada also hosted the ITA General Assembly and associated World Tunnel Congress in 2010 in Vancouver and during the TAC presidency of Rick Staples. The next TAC national tunneling conference in 2014 will be in the high Rocky Mountains city of Banff "and at a time when some of the snowy white stuff will be around", promised Staples. The next event in the Canada tunneling calendar is a workshop in Toronto on 29 November to introduce a 30-year, Can$30 billion investment in transit expansion for Toronto, with many of the projects including extensive underground structures.

Tunneling in Canada remains vital and progressive and the country remains committed and engaged in the wider tunneling community. TunnelTalk will continue to report the tunneling news from Canada as it happens.

References

Ottawa announces shortlist for LRT - TunnelTalk, November 2011
First tunnel award for Toronto Crosstown LRT - TunnelTalk, September 2012
Tunneling to commence in Toronto - TunnelTalk, May 2011
Governor signs California HSR funding bill - TunnelTalk, July 2012
Governor supports mega water tunnels project - TunnelTalk, July 2012
In Search of resilient cities - TunnelTalk, December 2011
Modern large diameter rock tunnels - TunnelTalk, April 2010
Epoch-making Gotthard Baseline - TunnelTalk, October 2010
Strabag to build Toronto wastewater tunnel - TunnelTalk, September 2011
Obituary - Dan Eisenstein - TunnelTalk, June 2009
ITA success at Vancouver - TunnelTalk, June 2010

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