GREAT BORES OF TOMORROW

Peter Collins

Record lengths of tunnels will be dug in 2014

M

ore than half the world now lives in towns; by 2030 the urban population will be close to 5 billion. Cities are running out of space, many are building upwards, with ever-taller skyscrapers. But they are also digging downwards, encouraged by the increasing sophistication of tunnel-boring machines.

In 2014, record lengths of tunnel will be bored - perhaps around 1000km (620 miles) in all. Boring machines will burrow beneath traffic-choked cities in China, India, the Middle East and Latin America to bring new or expanded subway systems. Add the massive water sewerage and other projects underway and the amount of tunneling in 2014 will be perhaps double that of five years earlier, reckons Lok Home, the boss of Robbins, an American maker of bores

BEYOND BORING

Tunneling will be completed on two large projects whose success should encourage city chiefs worldwide to be more ambitious. In Seattle, the world’s biggest bore, Bertha, will finish a job she began in August. The 17.5-metre-wide machine is burrowing under the west coast city to replace an ugly viaduct with an underground motorway.

 

Inside the Crossrail bbc.co.uk

Meanwhile, tunneling will finish on Crossrail, Europe's largest construction scheme. Eight bores (two of them, Phyliis and Ada, named by The Economist's deputy editor in a competition) are whirring beneath London's West End and the City to hollow out the central portion of a railway stretching from Heathrow airport in the west to Dockland and beyond in the east. Services will begin in 2018.

London is enjoying a subterranean renaissance. In the coming year planning permission will be granted for the Thames Tideway tunnel, a giant sewer to stop the capital's river from filling with ordure whenever heavy rains overwhelm its Victorian drains. And work has begun on the London Power Tunnels, a network of shafts that would carry electricity cables.

The rock beneath the Alps is starting to resemble Swiss cheese. The 55km Brenner Base Tunnel, being dug between Austria and Italy, and the 57km Gotthard Base Tunnel, under Switzerland will greatly rail capacity for both freight and passengers between Northern Europe and Italy taking traffic off clogged Alpine roads.

The Bertha

  Plans to bring water to thirsty cities are also keeping bores busy. South-east Asia's longest tunnel, at 45km, should be finished by the start of 2014. It will carry water to the region around Klang Valley, south of Malaysia's capital, Kuala Lumpur. California's governor, Jerry Brown, is proposing tunnels that would bring water from the hills around Sacramento to Los Angeles and Silicon Valley.

The Channel Tunnel dug between England and France in 1987-91, showed that bores could excavate beneath the sea at high pressure. The technology has kept improving. Projects that once seemed impossible are now feasible, says Werner Burger of Herrenknecht, a German firm whose machines are digging Crossrail.

Inside The Channel

Herrenknecht and Robbins are perhaps the best known of the handful of Western firms that make tunneling machines. Hitachi of Japan made Seattle's big Bertha.

Now there is competition from China. A division of the state-owned China Railway Group supplied some of the bores for Kuala Lumpur's metro expansion.

 Despite the boom, making big boring machines is not an easy business to succeed in. In 2008, Caterpillar, the world's largest maker of construction machinery, bought a small Canadian maker of tunneling machines, with a grand plan to become a force in the market. In 2014, it will stop producing them, having failed to make a decent return; it could not compete against smaller specialists like Herrenknecht and Robbins. The cost of the boring machines on a big project is in any case typically less than 5% of the total. But the machines make possible a vastly bigger industry of tunnel construction and associated works (including laying tracks, putting in signaling systems and building stations).

As technology matures, governments are becoming more adventurous. China has revived a previously abandoned plan to build the world's longest sea tunnel across the Bohai Strait, linking the cities of Dalian and Yantai.  Proposal for super-long tunnel linking South Korea to Japan and China and the Chinese mainland to Taiwan, which once seemed fantastical, are getting a fresh look. An exciting future beckons for boring.

Culled from THE WORLD IN 2014 published by The Economist