Thanks to new tunneling technologies, real estate trends are down. Way down.
It's the mantra of every silver-tongued real estate agent straining to close a deal: They're not making any more land. But imagine if they were. Suppose acres of new land could be manufactured just like I-beams, bolts of cloth, or toothpaste. And what if this man-made frontier could be rolled out anywhere, even in the heart of the densest metropolis, without displacing anyone?
Well, it can. The world's cities may be overcrowded, and the suburbs that surround them may be choked by unchecked sprawl, but there's plenty of undeveloped space. It's right at your feet: underground. There are 100 quadrillion cubic feet of undeveloped metropolitan real estate in this country alone, and that's counting just the first mile down. Think of it this way: If everyone in the entire country moved to Los Angeles, each of us could have 2 million cubic feet to house our stuff. How does that compare with where you live now?
You won't hear much talk of it outside of specialized engineering circles, but we're at a tipping point. The cost to burrow down is dropping, while the price (and hassle) of erecting a skyscraper in a dense urban area just keeps rising. The breakthrough comes thanks to tunneling technologies that are now being used on huge transportation projects, like Boston's Big Dig and Moscow's Lefortovo highway tunnel project. Over the next 10 years these techniques will be used to hollow out space beneath the world's great cities.
Until recently, tunneling required large crews to drill holes, cart out rock, and install lining. All of that manpower drove up costs, and not just because of wages earned. In the late 1960s, tunneling consultant Howard Handewith led a federal assessment of the practicality of building an ultrahigh-speed transportation link under the Northeast Corridor. What killed the project was the expense of constructing worker-escape shafts at 1-mile intervals. "Nobody," says Handewith, "wanted to have to travel 50 miles to get out if a situation came up."
Take humans out of the digging process and the price of a hole starts to fall. Automation began in the 1950s, when a mining engineer named James Robbins discovered that if you pushed a sharp-edged metal wheel over a rock surface with enough pressure, the rock would shatter. If the wheel - or, better, an array of wheels - kept rolling around and around, and the pressure was kept constant, you could dig deeper with each turn.
The civil engineering community was slow to adopt Robbins' tunnel-boring machine (TBM). The first couple of generations cut only a few feet an hour and frequently jammed. Plus, each machine cost about $10 million, so buying even one represented a huge capital expense. And whereas the old drill-and-blast method was inherently a batch process, tunnel boring is continuous. A whole new set of support systems had to be invented.
These problems have been solved. The latest TBMs can slice corridors 40 feet in diameter through almost any kind of terrain, including sand, at rates of up to 20 feet per hour. They can dig horizontally, vertically, even in spirals. High-speed conveyors suck the tailings out of the hole, while a robotic rig automatically snaps sheets of lining in place like huge Lego pieces. Today's drill-and-blast technique - used to create large chambers - is just as slick: The newest machines come with sensors that can calculate the proper size and shape of an explosive charge and drill it into the rock. On deck: an industry-specific XML dialect, recently hammered out by the International Rock Excavation Data Exchange Standard committee, that will allow these machines to talk to each other - as well as databases, simulators, and planning programs.
Within a decade, digs will be entirely automated, run by people sitting in aboveground trailers or even in offices a thousand miles away. Many small tunnels already are bored this way. Keeping humans away from the rock face lowers cost and saves lives. Even now, prices are in the same ballpark as conventional construction. The recently completed 7-mile Flém-Gudvangen tunnel in Norway came in at about $1.50 per cubic foot. A new Madrid metro line connecting the city with its airport was $15 per cubic foot. Translated to aboveground terms (and assuming the standard 10 feet between floor and ceiling), that's a competitive $15 to $150 per square foot. As the technology matures and the price per cubic foot falls, a wave of new applications will be unleashed: municipal, industrial, commercial, and, finally, residential.
Among the first wave of tunneling projects under way are subway extensions, highway re-siting projects, and petrochemical repositories. These will pave the way to further standardization and automation needed for transnational, Chunnel-type digs. The East - which has never been shy about big engineering - will likely plow down first, linking Japan and Korea, China and Japan, and Taiwan and China. The West might follow by tunneling under the Gibraltar and Bering straits.
The last stop on this train is the ultimate TBM megaproject: a supersonic world subway. Maglev trains running through depressurized tunnels are the logical successor to airplanes, at least between large cities. Magnetic levitation would eliminate rolling resistance, and the vacuum does the same to air resistance. The trains could "fly" down the tracks at many times the speed of the Concorde - without creating a sonic boom. In a couple of decades, we may see a world where major international cities are within a few hours' commute of each other.
By 2005, some under-urban highway projects will start to include parking lots. Where there is parking, malls will spring up. By 2008, developers might offer these retailers subterranean warehouse space, then offices, and, finally, full-fledged industrial parks. By 2013, we could see some hotels, probably marketed to international commuters and located just below the financial centers of Tokyo, London, and New York.
Some cities have already started to expand underground. Both Toronto and Montreal have extensive downtown retail complexes below the surface. "It keeps Montreal's core dense and lively," says Jacques Besner, a city spokesperson, "which can be a challenge in a climate like ours." Likewise, Kansas City has 20 million square feet of light industrial space sited in old quarries beneath the city. Commercial tenants prefer the location because the ambient temperature of Earth's crust - about 57 degrees Fahrenheit year-round - keeps energy costs low.
If history is any guide, artists will be the first to actually move underground full-time. They have a knack for converting industrial and commercial spaces into highly desirable residential real estate. Looking at their airy studios, we'll decide underground space isn't so dreary after all.
If they are large enough, caverns will feel like the outdoors; they might even be plumbed for "rain" and specially vented to create "wind." Artificial weather will keep the air crisp, while artificial light sources - from vast LED arrays, fiber pipes carrying light from the surface, genetically engineered extra-phosphorescent lichen - will infuse this superspace in an eternal dawn. Sunbathers, though, will need to call for the elevator.
It sounds far-fetched, but some in the public sector are convinced that tunnels are the urban future. Bill Vardoulis, the former mayor of Irvine, California, and its current chamber of commerce chair, is a passionate tunnel advocate. He argues that the easiest and cheapest way to lick the region's gridlock problems is to punch three holes through the mountains between Riverside and Orange counties. "People have been traveling underground for a long time," says Vardoulis. "The next step is to actually live there. It would certainly take getting used to, but to me it seems like a clear evolution. I think it's inevitable."
10 YEARS OF MEGA-ENGINEERING
1994
The Chunnel, a 31-mile steel-and-concrete rail tube connecting England and the Continent, opens to traffic.
1995
Major construction is completed on Japan's Akashi-Kaikyo Bridge, the longest suspension bridge in the world.
1998
The first plane lands at Hong Kong International Airport, a $20 billion artificial island that includes high-speed rail.
China's Ertan Hydropower Plant, the largest underground power facility in Asia, turns on the juice.
1999
Office workers in Kuala Lumpur move into the Petronas Towers, the world's tallest buildings at 1,453 feet.
2000
Norway's 15-mile Laerdal Tunnel, the longest road tunnel in the world, opens to the public.
2003
Boston's $14 billion Big Dig opens its I-90 connector, linking Mass Pike to the Ted Williams Tunnel and Logan Airport.
