Completion of the 57km long deep Gotthard rail tunnel in the Swiss Alps in May, the gathering momentum on London’s complex Crossrail project and the deployment of the world biggest tunnel boring machine (TBM) for a road in Italy this year are aspects of a construction industry sector that is booming like never before.
Tunnelling key to development
In the developing countries, particularly the upcoming BRIC (Brazil, Russia, India and China) economies, tunnelling is a key aspect of the infrastructure developments, and on an unprecedented scale. It is a trend that looks set to continue, driven by economic demand and made possible by a maturing of technology which makes projects safer and more reliable than in the past.
“In China, in India and other parts of Asia the growing cities all need metros, for example,” points out Doug Oakervee, a past president of the ICE and currently non-executive director for contractor Laing O’Rourke developing its business in Hong Kong.
They are building them on a staggering scale; Shanghai alone has had nearly 100 TBMs working on its system in recent years and since the first line was opened in 1995 has expanded its network to 11 lines with a total 434km of track.
“In China, in India and other parts of Asia the growing cities all need metros”
Another 400km of line is being added to what is already the world’s largest subway system.
But with 200 cities in China with populations over 1M people there is plenty of scope for more, and systems are underway in many of them. Guanzhou had 60 machines working last year and Kunming in the west is taking delivery of 12 earth pressure balance (EPB) tunnelling machines.
Hong Kong awards
Oakervee, with a five decade long history in tunnel building, is one of seven international judges for the second International Tunnel Awards, organised by NCE, which recognise and celebrates a sector of construction that is producing innovation, achievements and advances on a world scale. Appropriately enough it will be held in Hong Kong this September .
“Outside China, the region is also making some major projects at present,” says TC Chew, project director for the MTR in Hong Kong. “Here, of course, but also in Singapore, Kuala Lumpur (KL) and elsewhere.” KL has got at least three mass transit projects in train, he says, and Singapore is looking at a number of schemes including an immersed tube tunnel across the Marina Bay.
Schemes to link islands in the region are being considered he says. Hong Kong has just completed its massive water drainage tunnel project and is currently building a 26km long express rail link to China (NCE 3 March 2011) as well as new lines for the MTR.
But tunnelling developments are apace all around the world. The huge sprawl of Mexico City is currently seeing work on a new metro line and work has begun on the 60km total length of the huge Emisor sewer project. The Crossrail project driving 21km of twin rail tunnel underneath London is gathering pace and the 32km long Thames Tideway sewer project will follow.
Second of the great Alpine rail tunnels, the 55km long Brenner Base Tunnel, has been given the go-ahead by both the Austrian and Italian governments and Germany is building more than 20 tunnels for the same Euroroute as far as Berlin.
Innovation is a major part of the story
Economic need is part of the story, but so too is innovation. Tunnel technology has advanced enormously, says Oakervee, especially with TBMs which are now bigger, much more reliable and able to cope with mixed
and difficult ground.
Technology means tunnelling is now safer with work below ground requiring just as many “sophisticated technicians controlling electronic systems” as miners. “Japan has even been looking at tunnel construction controlled completely remotely from the surface and robotics is likely to increase,” Oakervee says.
Tacking these challenges, pushing the technology envelope, and advancing methodology are all making the tunnel sector one of the most exciting parts of engineering at present and likely to be so into the future.