Building the World's Longest Underwater Tunnel: Fehmarnbelt Link Construction

Fehmarnbelt Tunnel Project Overview

• 🇩🇰 A massive tunnel project, the Fehmarnbelt link, is under construction in southern Denmark, connecting the country to Germany.
• 🌍 It is currently Europe's largest construction site and the world's longest prefabricated road and rail tunnel.
• 💰 Costing over €7 billion, primarily financed by Denmark, it's part of an EU plan to enhance travel links between northern and southern Europe.

Tunnel Construction and Scale

• 🏗️ The construction site spans an area equivalent to 600 football pitches, where tunnel segments are being molded from steel and concrete.
• 📏 Each segment is over 200 meters long, and 90 segments will be joined together like Lego bricks to form the 18 km long tunnel.
• 🚢 The tunnel will be floated out and lowered into a trench dug into the seabed with 15 mm precision, with each segment weighing 73,000 tons.

Engineering and Challenges

• 🛠️ A 'pin and catch' system is used to precisely position new segments against existing ones, with huge steel doors managing the water.
• 🌊 The bedrock was too soft for drilling, making a tunnel a more secure option than a bridge, which would also face risks from ship collisions.
• 🌊 The water depth of 30 meters allows the largest ships to sail over the tunnel.

Project Impact and Timeline

• ⏱️ The project has been in development for nearly two decades, overcoming lawsuits and environmental opposition.
• 🚄 The tunnel is expected to cut the rail journey between Copenhagen and Hamburg from 4.5 hours to 2.5 hours.
• 🚗 It will also reduce a 45-minute ferry crossing to a drive of less than 10 minutes.
• 📈 The project is anticipated to boost the local economy and is slated to open in five years, bringing Scandinavia closer to mainland Europe.