Hong Kong, China: Rush hour traffic flows quickly through the Cross- Harbour . It’s one of the world’s most traveled highways and connects Kowloon with Hong Kong Island (in the background)

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Arteries underground 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 .” 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- 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 – 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 in Cologne, . “For everyone in the ciation (ITA), at the World Tunnel Con- ogra P

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- >

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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 M

eu industry has often been a major source of inspiration for tunnel construction tech- nology. The similarities, between these /Science /Science Mu S

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 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 in Munich.“However, in terms of transpor- ogra P 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,

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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 In the early days of modern tunnel construction, working under high pres-

P Photogra sure was especially dangerous, because >

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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 how many tunnels are being constructed during a tunnel’s construction as well as Tunnel in , 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. These users have to be plains Dr. Jürgen Bönig from the Museum beginning, on the basis of a specific haz- directed to safe areas if there is an acci- of Work in Hamburg. ard assessment. Medek understands these dent or a fire. The differences between processes in detail, because Dräger has the various modes of transportation are Working Under Pressure developed into a supplier of holistic safety much more apparent during a tunnel’s Nowadays, slurry-supported shield tun- systems for tunnel construction built on operation than when it is being built. The neling technology has reduced the im- the foundation of its extensive portfolio of conditions in a pedestrian tunnel, for ex- portance of manual tunnel construction around 60 products and many services. ample, are very different from those found under high pressure, and the cutters in “We are already engaged in the early in a road tunnel or a railway tunnel. the cutting wheels of today’s tunnel bor- stages of new construction and or ren- The world’s longest tunnels are used ing machines can even be replaced at nor- ovation projects so that we can provide for railway, and a variety of safety con-

mal atmospheric pressure. This technol- all of the necessary services,” explains cepts have been established for them. aas h ogy had its debut in the cutting wheel of Medek. The tasks involved include pro- Deutsche Bahn AG, for example, has de- obert

Herrenknecht’s tunnel boring machine viding consultation during the develop- veloped a multistage safety concept for its r

“Trude,” which was used to create the ment of the safety concept, training work- tunnels. “The first stage consists of pre- ase, h fourth tube of Hamburg’s new Elbe tun- ers and rescue crews, supplying rescue ventative measures, followed by event-al- obias nel. However, tunneling work is still done chambers and personal protective equip- leviating actions,” explains Klaus-Jürgen t using pressurized air in many places ment, in addition to offering a flexible Bieger, Head of Safety and Chief Fire Pro- lliance/ around the world. rental management system for a broad tection Officer of Deutsche Bahn AG. In a Especially in recent years, one of the range of safety technologies. The services the next stage, the victims either man- technical solutions used to improve safety include making sure that the respiratory age to flee from the accident site or are

at tunnel construction sites worldwide is protection systems are always in working externally rescued. In order to prevent P; Picture- DPa the rescue chamber. These containers order for the fire departments that are re- accidents and fires, trains with passen- are pressure-sealed and gastight. They sponsible for the various tunnels. To en- gers and freight are not allowed to pass

are equipped with an oxygen and energy sure respiratory protection, Dräger sup- in long tunnels with high-speed rail lines. a DDP images/ supply system that is independent of the plies closed-circuit breathing apparatuses In addition, passenger rail cars have to hy: surrounding environment, and allow oc- (e.g. Dräger PSS BG 4 plus) that can op- comply with the Federal Railway Authori-

cupants to communicate with the outside erate for up to four hours, enabling wear- ty’s fire protection regulations in order to > P Photogra

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Rescue chambers increase the level of safety

Following an acci- dent in March 2012, rescue helicopters landed in front of the portal of the sierre Tunnel in switzerland

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Mulitlevel: Preventive measures are followed by measures to save oneself and others

> be approved for registration in Germany. These regulations are based on the DIN 5510 standard, supplemented by the cur- rent version, of the as yet unpublished, DIN CEN/ TS 45545-1 standard. If a fire should nonetheless break out on a train, measures such as an emergency braking override system will ensure that the train doesn’t stop until it has left the tunnel. If all of these precautionary mea- sures fail to prevent a critical incident from occurring in a tunnel, the passen- gers will either flee to safety or be res- cued by firefighters. The rescue concept is supplemented by structural measures such as specially protected escape routes and lighting systems, escape route signs, emergency exits, and emergency tele- phones. In new tunnels such measures are augmented by additional features, such as built-in fire extinguishing pipe- lines including the reservoir, power sup- ply systems, and wireless infrastructure. Fast Rescue Trains While the approaches to tunnel portals and rescue missions are designed to ac- commodate road vehicles, road-rail vehi- cles, and rescue trains, representing spe- cial types of rescue technologies. Germany has six rescue trains, which are stationed along the high-speed rail lines between and Würzburg and between Mannheim and Stuttgart. Schweizerische Bundesbahnen (SBB) in Switzerland op- erates a total of 15 firefighting and res- cue trains. In 2006 SBB ordered eight new trains that were built by a consor- tium in which Dräger was responsible for the safety technology. These trains, which

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EN_08-17_Tunnel.indd 14 07.06.12 08:21 Safety in the Eurotunnel: Testing a high-pressure fire-extinguishing system (left). On the right: the connecting door to one of the cross-cuts that connect the two main tun- nels with the technologies that lies between them

can travel up to 100 km/h, consist of a res- ing truck releases a huge amount of toxic cue car and and a self-propelled fire en- substances.” gine carrying a tank pumber in between. In a research project commissioned The emergency room can evacuate up to by the Federal Highway Research Insti- 60 individuals. tute, occupational safety experts tested “Evacuating people from road tun- various measures for quickly and reliably nels during a fire is a major challenge, be- guiding people from their vehicles to cause most people instinctively think that the emergency exits. They tested psycho- their car is the safest place in the tunnel,” acoustic means as well as innovative sig- says the psychologist Professor Berthold naling technology. As an acting sublimi- Färber, who heads the Human Factors In- nal alarm signal, according to Prof. Fär- stitute at the Universität der Bundeswehr ber, a low frequency sound proved to be in Munich. “In subjective terms, a vehi- effective, while birdsong unterlaid with cle is a protective space. However, if fire “white noise”, pointed people to the breaks out in a tunnel people only have a emergency exit. The way to the exits were few minutes to escape,” he says. “A burn- marked by the researchers with running >

Combating tunnel fires with water mist From 2009 to 2012, the “safety of life in tunnels 2” (solit2) project investigated technical systems for fire protection in tunnels. as part of the project, which was financially supported by the german Federal Ministry of economics and technology, e Masson l more than 30 simulations of major fires were carried out in summer 2011 in order to test the effectiveness of water mist fire fighting systems in connection with fire ventila- tion in highway tunnels. these simulations were carried out in the “tunnel safety testing” test tunnel in san Pedro de anes, spain. in the process, liquid fires and solid

areth Fuller, Pierre material fires with fire loads of up to 100 megawatts were simulated. e/ g

C at the stuva conference in Berlin in 2011, Dr. roland leucker (Managing Director of stuva) and stefan Kratzmeir (Managing Director of iFaB – i nstitute for applied llian a Fire safety research) concluded that the project had been successful. they said that ture- C the use of water mist systems can favorably affect the development of liquid fires Simulation: FogTec a Pi and solid material fires in a tunnel, as the finely distributed drops of water cool off the tests extinguish- ing methods using C; DP burning material and, its surroundings , and also alleviates the level of smoke. water mist under ogte additionally, the use of water mist reduces the danger of fire flashing over onto other realistic conditions hy: F vehicles. “in general, it’s important to activate the system as early as possible so that the positive effect of the cooling occurs sooner,” wrote the two experts in a joint

P Photogra article in the trade magazine tunnel (issue 8/2011).

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EN_08-17_Tunnel.indd 15 07.06.12 08:21 A low-frequency sound has proved to be effective as a subliminally alarm signal

> lights, the escape door had a pulsating la- employed at the Stachus underground Tunnel system ser marking the exit across the tunnel. complex. The seal was granted after a ren- Bodio ovation of the complex, which is one of Eu- portal 12,000 New Sprinkler Heads rope’s largest underground structures and Combined station Emergency Technical aspects of fire protection play includes about eight kilometers of under- station Sedrun Shaft I an important role in tunnel safety, begin- ground escape routes. As part of the reno- Shaft II ning with pedestrian tunnels and large vation, the fire protection system was up- Combined station underground constructions that are used graded and 12,000 new sprinkler heads Erstfeld Emergency by many passers-by. For example, in Feb- were installed. portal station Cable tunnel ruary 2012 Munich’s municipal utility Another type of fire protection tech-

Access company was awarded the distinguished nology was chosen by the operators of the tunnel “Sprinkler Protected” seal of quality, from Dartford Tunnel and the Tyne Tunnels in Exhaust air Emergency the Federal Association for Fire Protection the UK, which are part of the M25 and M9 station Technology, for the fire protection system highways. The Tyne Tunnels have been in

3,000

Geology as a challenge: When the Gotthard Base Tunnel was being excavated, a whole 2,000 range of rock had to be drilled through. This posed big challenges for the tunnel constructors. Among other things, Final breakthrough they had to combine Sedrun on March 23, 2011 mechanical excavation and blasting technology

1,000

Combined station Sedrun East tube 13.7 km North portal Erstfeld Amsteg access 8.7 km tunnel West tube 0 11.3 km

7.7 km

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EN_08-17_Tunnel.indd 16 07.06.12 08:22 TUNNEL FOCUS PHOTOGRAPHY: CROSSRAILPHOTOGRAPHY: LTD A view of the Crossrail tunnel construction site in London. It is part of a 21-kilometer-long network that will connect 37 stations

operation since November 2010, and the An overview of tunnel construction Dartford Tunnel tubes will be equipped Shield Tunneling: A tunnel boring machine mills off the surface soil with high-pressure fire extinguishing tech- with a rotating cutting wheel. The tip of the machine is surrounded by a nology from Fogtec, a German firm. “The cylindrical shield. Depending on the site’s , the tunnel face is extinguishing water is atomized by means supported by a slurry under pressure or by the excavated material itself. of special nozzles, so that a comparatively In solid rock, the excavated material can be simply crushed and taken low amount of water with extremely high away. As soon as the tunnel has been excavated, the tube is firmly secured surface area combats the fire,” says Dirk and its inner surface is lined. Laibach, Technical Manager at Fogtec. Mine Tunneling: In this traditional mining procedure, holes are drilled into the existing rock so that it can be blasted apart in a targeted manner. Sophisticated Fighting Technology Subsequently the miners drill tunnels through the rock with hydraulic The company has installed the same tech- excavators. The modern version of this traditional mining technique is called nology in the Eurotunnel, which lies un- the “New Austrian Tunneling Method.” der the English Channel between England Cut-and-Cover: This type of construction is often used to build tunnels and France. Here there are four “safe sta- that lie close to the surface and for large underground constructions tions,” into which the truck-carrying shut- such as subway stations. An open excavation pit is dug, the tunnel is tle trains are automatically guided to if a constructed, and finally the site is covered with a ceiling. In a variant fire is detected on board. Once the site of process, only the walls and ceiling are built and the excavation of the the fire has been identified by the redun- tunnel is carried out underground. dantly installed measuring technology, the Caisson Construction: Tunnels under rivers or estuaries can be fire extinguishing technology, around the constructed by connecting a series of caissons underwater. This was the site, is released with a valve pressure of up procedure used for the first three tubes of the new Elbe Tunnel in Hamburg. to 100 bar. The water mist that is released cools the surface of the burning object im- mediately and simultaneously reduces the influx of oxygen. Roland Leucker, the Managing Direc- tor of STUVA, also mentions building fire protection measures based on, for exam- ple, the construction of the inner shells

Faido access of tunnels with a type of concrete that has tunnel South portal been mixed with polypropylene fibers. In Bodio case of fire, this prevents the concrete 15.6 km overlay from extensively spalling off from the steel reinforcements. This type of con- crete has already been used in the Cross- rail Tunnels in London. Peter Thomas

For information on Dräger products:

ILLUSTRATION: DIETERILLUSTRATION: DUNEKA; SOURCE: ALPTRANSIT GOTTHARD AG, ETH ZÜRICH, WIKIPEDIA www.draeger.com/105/tunnel

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