Hong Kong, China: Rush hour traffic flows quickly through the Cross- Harbour Tunnel. It’s one of the world’s most traveled highways and connects Kowloon with Hong Kong Island (in the background) 8 Dräger review 105 | 2 / 2012 EN_08-17_Tunnel.indd 8 07.06.12 08:20 Tunnel Focus Arteries underground Tunnel construction sites are extreme places that require complex solutions to make them safe. even the later operation, of the underground facilities for transport and infrastructure, makes high demands. eep beneath the city center in transportaion tunnels.” But the new long- London, UK, gigantic machines distance roads and rail tunnels need larger Dare working their way through and greater dimensions. clay and chalk. In spring 2012 the first of As a result, not only the number of tun- eight tunnel boring machines, from the nels, but also their lengths are growing. German manufacturer Herrenknecht, One example of this is the 55-kilometer- began to drill more than 40 kilometers long Brenner Base Tunnel, whose con- of rail tunnels under the British capital. struction is soon to begin. The Brenner These tunnels are at the heart of the Cross- Pass currently the most important and rail Project, which will channel long-dis- busiest north-south connection in the Alps. tance rail transport under London in the Around two million trucks and 12 million future. The massive project is currently cars drive through this bottleneck every the biggest construction site in Europe. year. The planned base tunnel, which will be solely for rail use, will run underground Rapid Growth between Innsbruck and Franzensfeste, and Many new tunnels are being built in should greatly reduce traffic congestion. similar mammoth projects all over the Building on exploratory galleries began in world, because the future of transporta- 2007, and construction of the main tun- tion infrastructure lies underground. Af- nel will begin in 2013. The project, which ter all, high-speed rail lines and highways will cost about eight billion euros, and is need tunnels; and high-performance tran- expected to be completed in 2022. sit systems in congested cities need un- derground tubes, so that they can go on Rescue concepts Required growing. Besides tunnels for passenger Also the diameters are larger: Opened in transport, networks must also be built 2009, the Changjiang Under River Tun- for data and energy transmission, water nel in Shanghai is divided into two tubes, pipes, and sewer systems. each with more than 15 meters in diam- Tunnels are the arteries of cities, eter. This provides enough space for a creating increasingly dense networks of three-lane highway plus a subway line un- structures beneath the earth’s surface. derneath. As tunnel projects become more Hundreds of kilometers of tunnels are cur- ambitious, safety requirements increase rently being built or planned worldwide. as well – not only during construction, but “The priorities are especially in Europe also during later operation. The fact that and Asia, “ says the construction engineer safety at tunnel construction sites has to Roland Leucker, Managing Director of the be further improved was emphasized by nonprofit Research Association for Under- In-Mo Lee, President of the International ground Transportation Facilities (STUVA) Tunneling and Underground Space Asso- hy: hy: Corbis P in Cologne, Germany. “For everyone in the ciation (ITA), at the World Tunnel Con- ogra T megacities, with their several Million in- gress 2011 in Helsinki. “It’s essential for P h o habitants, there is a huge need for public us to develop technologies that will en- > Dräger review 105 | 2 / 2012 9 EN_08-17_Tunnel.indd 9 07.06.12 08:20 Focus Tunnel Mining and tunnel construction largely use the same technologies and tools structure. Perhaps that’s why the mining M eu industry has often been a major source of S inspiration for tunnel construction tech- nology. The similarities, between these /Science /Science Mu l two types of excavation, have been a con- sistent feature ever since the first tunnels o / SSP T were built for irrigation purposes over 3,000 years ago. “For a long time, the ung Pho T methods and equipment used in excava- tions were largely the same as those asso- che Zei TS ciated with tunnel construction and min- ing,” says Dirk Bühler, Ph.D. Engineer and hy: hy: SüDDeu Tunnel Expert at the Deutsches Museum P in Munich.“However, in terms of transpor- ogra T tation, tunnel construction differed from P h o mining with regard to slopes, cross-sec- commissioned in 1908: The 1481-meter-long Rother hithe Tunnel runs under the Thames River tions, and surface features.” Werner Ochse, a tunnel expert at Dräger, adds, “There are also technical > able us to protect and rescue people even similarities between mining and tunnel- more effectively after accidents, especially ing when it comes to safety technology.” in the case of fire,” he said in an interview The Lübeck-based company’s long experi- with the trade magazine tunnels et espace ence with mine rescue operations is the souterrain. This applies especially to very foundation on which the firm’s current long tunnels, whose numbers are steadily range of safety equipment, for tunnel con- increasing. struction, is based. An impression of how tunnel workers conditions like those in a mine were protected in past centuries is pre- The safety concept for the construction sented by a replica of the Simplon Tunnel and operation of tunnels is complex, as is construction site, which can be viewed in demonstrated by the large number of rele- the Deutsches Museum’s permanent exhi- vant ordinances and regulations. Because bition. The first tube of this almost 20-kilo- of the unusual conditions at the construc- meter-long tunnel connecting Switzerland tion sites and in completed tunnels, many and Italy was built between 1898 and 1912. issues need to be addressed. They include The solid wood support structure leaves occupational safety, accident prevention, enough room for a mine railway in the fire protection, and safe escape routes. lower half of the tunnel profile. Above it, The similarities to mining operations numerous roughly cut tree trunks create are especially apparent during a tunnel’s a claustrophobic tangle of closely spaced excavation and the building of its support pillars. If you add poor lighting and heat, 10 Dräger review 105 | 2 / 2012 EN_08-17_Tunnel.indd 10 07.06.12 08:21 Rescue cham- bers offer hours, or even days, of self-contained underground protection – from toxic gases you can get an impression of the conditions under which the workers built the world’s first major traffic tunnel. Ongoing Construction Site Risks Conditions have changed considerably since then, thanks to electrical lighting, high-performance ventilation systems, and, above all, ultramodern tunnel exca- vation equipment. Tunnel construction was significantly transformed by large tunnel boring machines, which resemble underground factories consisting of ev- erything from the tunneling shield to the tubing installation system. “In Germany, shield tunneling is used primarily to con- struct railway tunnels,” says Leucker. Road tunnels, on the other hand, are still often made using mining processes, due to the need to have flexible profiles. Open- pit construction also continues to play a major role; this technique is used for around 20 percent of the tunnel stretches built in Germany today. The basic risks of tunnel construction (2) have remained unchanged. The tunnel- gaa ing route has to be protected primarily o. K c against geological factors such as water & ag penetration and rock pressure. In addi- K tion, workers have to be protected against the effects of blasting, tunnel boring, traf- Breakthrough: fic, and the building of the support struc- On March 23, 2011, the tunnel boring machine tures, as well as possible fires and their “Heidi” created the consequences. There are also specific chweiz/laif; Drägerwer final section of the s risks associated with a hard-to-reach un- west tube of the Got- thard Base Tunnel, derground sites that depend on external which is scheduled to energy supplies and ventilation. be inaugurated in 2016 hy: Keystone P In the early days of modern tunnel construction, working under high pres- Photogra sure was especially dangerous, because > Dräger review 105 | 2 / 2012 11 EN_08-17_Tunnel.indd 11 07.06.12 10:47 The German automobile club classifies the safety concept of the Richard Strauss Tunnel in Munich as “very good” > insufficient decompression could cause world. The eight Herrenknecht tunnel ers to work in typical scenarios involving the workers to suffer from Caisson Dis- boring machines being used in the Cross- long assignment times. ease, which is similar to the bends. A rail project in London are equipped with milestone in the prevention of this dis- rescue chambers from Dräger. “This tech- Multistage Safety Concepts ease was achieved by a physician couple nology has great potential, considering Preventive fire protection is necessary during construction of the St. Pauli Elbe how many tunnels are being constructed during a tunnel’s construction as well as Tunnel in Hamburg, Germany. “For the worldwide using shield tunneling,” says its operation. However, the measures used first time ever, from 1909 to 1910 Arthur Werner Ochse from Dräger. for ensuring tunnel safety are different and Olga Adele Bornstein monitored the According to Dräger Sales Engineer during operation than during the tunnel’s workers on a caisson or compressed air Peter Medek, the organizers of a new tun- excavation and the building of its support construction site. The couple systemati- nel construction project, or the upgrade structure. That’s because a tunnel is uti- cally combated the disease, using meth- of an existing system, should develop a lized by a great amount of people once it ods that they enhanced themselves,” ex- consistent safety concept from the very has been opened.