“Hamburg-Mitte-Elbe Tunnel” by Anita Janda, 2019. CC4.0 wikimedia. Included with appreciation.
Ten years to plan, nine years to build, seven billion to budget: the Fehmarnbelt Fixed Link Tunnel will offer an alternative to a 45-minute ferry between Germany’s Fehmarn island and Denmark’s Lolland isle. The new tunnel will clock travel time to ten minutes by car and seven minutes by train. Not just a faster trip between islands, Fehmarnbelt will reduce passage duration between Copenhagen and Hamburg.
Fehmarnbelt Fixed Link Tunnel will shorten the travel time between Copenhagen and Hamburg. Image: “Fehmarn bridge” by Bowzer. CC by SA 3.0, wikimedia. Included with appreciation.
It will be the world’s longest immersed tunnel, although at 11.1 miles long (18 kilometers) shorter than the Channel Tunnel stretching 31 miles (50 kilometers). Other differences include construction methods. The Channel Tunnel was built using a traditional boring machine. Fehmarnbelt will be pre-fab: tunnel sections completed on land will be submerged and then connected. Each section is 711 feet long (217 meters) – about half the size of a large container ship. All that length is heavy – each section weighs as much as 13,000 elephants.
One section of the tunnel’s pre-fab building blocks weighs as much as 13 elephants. Image: “Elephant,” by Felix Andrew, 2005. Public domain gnu. Included with appreciation.
In a world where the environment is part of every decision, Fehmarnbelt Fixed Link will include newly established stone reefs on both Danish and German sides, similar in some ways to the natural paths fashioned along the New River of England. Tunnels offer other environmental advantages, bringing automobiles, trains, and trucks below the surface where emissions be captured, if the tunnels are so equipped.
SMART Tunnel in Kuala Lumpur, Malaysia, combines transport and flood control. Image: “SMART tunnel entrance,” by David Boey, 2018. Wikimedia CC4.0. Included with appreciation.
Another environmental advantage of tunnels is response to flash floods. The Stormwater Management and Road Tunnel (SMART) in Kuala Lumpur, Malaysia, is designed to divert rainwater into a lower section, allowing the upper section to remain open to vehicular traffic. Floodwater diversion, storage, and reuse options are certain to present problems (and opportunities) in our future: can tunnels be part of the solution?
Thanks to Cherie E. Potts for suggesting this post, and to Frank P. Davidson for proposing and achieving the success of the Channel Tunnel.
Fehmarnbelt Fixed Link. “Why we’re building the Fehmarnbelt fixed link.” Femern. https://femern.com
Underwater tunnels like the Channel Tunnel, and Japan’s new tunnel under the Tsugaru Strait, are engineering feats. Here, “Underwater tunnel in Mandalay Bay Aquarium” photo by Daniel Ramirez, 2014. Creative Commons 2.0. Included with appreciation.
Walking on water takes a miracle, but walking through water requires excellent planning. When the Channel Tunnel was first designed, over a luncheon meeting in New York City hosted by Frank P. Davidson, Thomas Lamont, and representatives of Bechtel, Brown & Root, and Morrison Knudsen Company, a 1959 decision saved lives in 2022. The group engaged Charles Dunn of International Engineering Company of San Francisco, CA, to design the project. Dunn added a service tunnel. It was not mandatory, but it proved prescient.
Channel Tunnel has three tunnels – two rail lines and a service tunnel between. The design by Charles Dunn has saved lives. Image: “Cross section with service tunnel in between two rail lines,’ by Commander Keane and Arz. Wikimedia commons. Public domain. Included with appreciation.
The three tunnels under the Channel (in French, “La Manche”) are a north-running tunnel, a south-running tunnel, and – between them – a service tunnel. During an August 2022 incident, a train experienced an alarm warning, stopped, and held for assessment. Passengers walked for 15 minutes from the rail shuttle to a freight train that conveyed them through and out of the service tunnel. That freight train did not have the usual accommodation for passengers: no elegant meal service, not even seats. But with Dunn’s design, the service tunnel, and its freight train did provide safety. When passengers arrived in Folkestone, terminal restaurants welcomed them with free food and beverages.
Strait of Dover between England and France. Image: NASA, 2000. Public Domain. Included with appreciation.
The service tunnel in the Channel Tunnel has proven its worth before. In 1996, a fire broke out in the Channel Tunnel when a train carrying heavy goods vehicles (there are passenger trains as well as freight trains carrying trucks) sparked a fire. The train was brought to a controlled stop adjacent to an entrance to the service tunnel. While there were no reported fatalities, some people suffered from smoke inhalation. The fire was fought by English and French teams who extinguished the flames after considerable effort. Tunnel repair was carried out by Freyssinet, a French engineering firm. Bi-national Channel Tunnel Safety Authority (CTSA) chaired one of three inquiries: the result was regular bi-national team practice exercises and shared operational procedures. In 2008, a fire in the Chunnel, started by a truck that spread to other vehicles, caused damage but no fatalities or serious injuries. It is worth noting that when the Channel Tunnel project began, the service tunnel was the first built.
“Tsugaru Srait” by Kyoyaku, adapted by Bourrichon, 2019. Creative Commons 4.0. Included with appreciation.
How can the Channel Tunnel’s design inspire the future? Japan, home to many tunnels that connect the nation composed of four main islands – Hokkaido, Honshu, Kyushu, and Shikoku – is currently planning a new tunnel across the Tsugaru Strait for automobile traffic between Honshu and Hokkaido. The tunnel would span 31 kilometers (19. 26 miles) and cost about $7 billion (720 billion yen). In the new Tsugaru Strait tunnel, there will be two decks: the top for autonomous vehicles like self-driving cars; the lower for freight trains. Economic benefits include increased ability to transport agricultural produce from Hokkaido, estimated at 34 billion yen ($249 million). The project will take 15 years to build; construction costs would be recouped in 32 years. Tolls are estimated to be 9,000 yen for cars ($65).
“Platooning” is a method for linking controls of lines and groups of autonomous vehicles. Could this be used in the new Tsugaru Strait Tunnel? Image: “Platooning Back” by U.S. Department of Transportation, 2019. Public Domain. Included with appreciation.
Tsugaru Strait is also the location of Japan’s Seikan Tunnel, serving only trains; it was not built with a separate escape or service tunnel, but with two emergency escape points in the system, Tappi-Kaitei station and Toshioka-Kaitei station. Shinkansen trains in Japan’s high speed rail network use the Seikan system. Fifty trains traverse the Seikan Tunnel every day, and night trains offer sleeping accommodation. Seikan suffered inundation accidents during construction but no fatalities.
“Cross-Harbour Tunnel Bridge Fire,” in Hong Kong, 2019. Photograph by Studio Incendo. Wikimedia. Included with appreciation.
Other tunnels around the world have experienced accidents, fires, and floods. In Hong Kong, the Cross-Harbour Tunnel was the first built there for underwater transit; in 2019, protestors set fire to tollbooths, causing the tunnel to close but avoiding any fatalities. In 1991, two trains collided in the Severn Tunnel joining England and Wales; 185 passengers were injured but none fatally. In 1999, a fire in the Mont Blanc Tunnel joining France, Italy, and Switzerland, caused 39 deaths and 14 non-fatal injuries. These examples point out the wisdom of Dunn’s design of an extra service tunnel for the Channel Tunnel.
“Shadertoy Tunnel Example,” by Inigo Quilez, 2016. Creative Commons, wikimedia. Included with appreciation.
In a time of budget cuts, along with an increased focus on transportation infrastructure, this week’s Channel Tunnel problem and its successful rescue solution may serve to underscore the importance of safety, and its support by budget and planning. In a new era when safety measures for autonomous vehicles and driverless cars are forefront, Japan’s new tunnel may set an important example for tunnel transport infrastructure for autonomous vehicles. What safety measures should be included?
A higher purpose, above ground; a safer world, below. Why not send cars and trucks underground, where new roads for autonomous vehicles might be easier to build? Elon Musk, of Tesla and SpaceX fame, envisions cars positioned on platforms that descend to traverse networks below ground. A similar design was earlier suggested by David Gordon Wilson of MIT whose palleted highways would increase speed and decrease accidents. Tunnels have changed transport around the world: the Channel Tunnel and the Mount Blanc Tunnel are recent examples. Boston depressed the Central Artery, resulting in a Greenway atop with a special park called the Mothers’ Walk. Nearby, walk towards a better world with the Louis D. Brown Peace Institute for the Mother’s Day Walk for Peace. Will Elon Musk’s underground highways promote a cleaner, safer environment with more parks above where people can walk and nature flourish? It’s an exciting idea with a name that belies the innovation: The Boring Company.
Building the World Blog by Kathleen Lusk Brooke and Zoe G Quinn is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
The Gotthard Base Tunnel, world’s longest, opened to fanfare and diplomacy, and a ballet corps of 600, in June 2016. The Gotthard massif has long challenged transport efforts; Gotthard now joins the Mont Blanc Tunnel in traversing mountainous terrain. Boston’s Central Artery/Tunnel Project also features a tunnel to bring vehicular traffic underground while a new greenway park graces the urban landscape above. Tunnels are an ancient instinct: moles know the routes underground, while human endeavors appear to have been early home-improvement projects by cave dwellers adding a second room. Land tunnels preceded water transit ways such as the Channel Tunnel. But all tunnels have one aspect in common: emissions trapped in a contained environment. Research contrasting on-road carbonyl emission factors in two highway tunnels, Caldecott Tunnel near San Francisco, California and Tuscarora Mountain Tunnel in Pennsylvania, was conducted 2002. WSP|Parsons Brinckerhoff recommended jet fans to move fumes through long road tunnels. But could there be a better solution? Will the EPA‘s capture and sequestration research apply to tunnels? Might ExxonMobil and FuelCell Energy‘s innovation to cleanse carbon dioxide from the exhaust of natural gas- and coal-fired plants be applied to other situations? Carbon capture could take on a new meaning if tomorrow’s tunnels might become channels for environmental improvement.
Building the World Blog by Kathleen Lusk Brooke and Zoe G Quinn is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License
Favorite of skiers, the Alps stand between France, Italy, and extend into Switzerland; the highest peak is Mont Blanc, elevation 15, 771 feet (4,807 meters). When France and Italy built a tunnel in 1965 between Chamonix-Mont Blanc and Courmayeur, the Mont Blanc Vehicular Tunnel was successful, perhaps beyond the limits of its single-bore two-way design, originally specified for 350,000 vehicles but soon accommodating over 2,000,000, many trucks. When a truck carrying margarine and flour caught fire in the middle of the tunnel in 1999, temperatures rose rapidly in the contained tunnel environment, escalating to over 1,800 F (1,000 C) and causing tires on nearby cars and trucks to explode as asphalt was in a meltdown. More than 40 fatalities resulted. In comparison, when a 1996 fire broke out in the Channel Tunnel, lives were spared by advance thinking of a design demanding three bores: one each way and one service tunnel, used by Eurostar passengers to walk to safety. But can tunnels be made even safer in the future by the addition of pallet transport? Or might tunnel sensors coordinate with driverless trucks and cars?
Map of the location of the Salang Tunnel from the BBC at bbc.co.uk.
When the Salang Tunnel, cutting through the Hindu Kush mountains in Afghanistan opened in 1964, much like the Mont Blanc Tunnel cutting through the Alps, is was heralded as a major feat of engineering. Fast forward nearly 50 years, and lack of upkeep and overuse has led this modern marvel to a dangerous state of disrepair. The volume of cars and trucks has increased ten fold, the road at some points is a dirt path, and the tunnel itself is barely large enough to allow the passing of many shipping trucks. So why is this tunnel still used? Because Pakistan has closed its boarders to NATO and other travellers, leaving the Salang Tunnel as the only optionfor travel. For more information on the tunnel and its role in Afghanistan today, please visit: http://www.npr.org/2012/06/24/155302587/afghan-tunnel-decrepit-dangerous-yet-indispensible?sc=17&f=1001
