Modern infrastructure increasingly relies on tunnels to overcome geographical barriers, reducing travel times and improving connectivity. While many tunnels provide brief underground passages, a select few push the boundaries of engineering, stretching for miles beneath mountains and even under the sea. These long road tunnels showcase cutting-edge construction techniques and are crucial for maintaining transportation in challenging environments.
Ryfylke Tunnel, Norway – A Subsea Breakthrough
At 8.98 miles (14.46km) in length, the Ryfylke Tunnel currently holds the title of the world’s longest undersea road tunnel. Completed in 2019 after seven years of construction, it connects Stavanger and Ryfylke in Norway, significantly reducing reliance on ferry crossings.
The project cost 6.4 billion Norwegian Kroner (£460 million) and includes a toll system to recoup construction expenses, with discounted rates for electric vehicles. The tunnel descends to a depth of 285 meters below sea level and consists of two separate tubes, each with two lanes, capable of handling up to 10,000 vehicles daily. However, the Rogfast project – an ongoing initiative to connect islands via undersea tunnels – suggests Ryfylke’s reign may be temporary.
Zigana Tunnel, Türkiye – Conquering Mountain Terrain
The Zigana Tunnel in Türkiye measures 8.99 miles (14.48km) long and bypasses the snow-prone Zigana Pass, providing a vital all-weather route. Finished in 2023 after beginning construction in 2016, it cuts journey times by approximately 20 minutes in summer and ensures passage during harsh winters.
Built using the New Austrian Tunnelling Method, which adapts to rock conditions during excavation, the tunnel features two separate tubes with 16 laybys each, six ventilation shafts, 40 connecting tunnels, and nine transformer rooms. This complex infrastructure ensures smooth traffic flow and reliable operation.
Muzhailing Tunnel, China – Resilience in Seismic Zones
The Muzhailing Tunnel in China’s Gansu Province extends 9.46 miles (15.22km) and presents a unique set of construction challenges. Built at high altitude in an earthquake-prone region, the tunnel relies on NPR anchor cabling technology to secure its structure against seismic activity and ground deformation.
This innovative method allows the tunnel to withstand shifts in the surrounding rock, ensuring stability in an otherwise unstable environment. The Muzhailing Tunnel stands as a testament to engineering ingenuity in extreme conditions.
Conclusion: These tunnels represent more than just roads; they are feats of modern engineering that connect communities, overcome geographical obstacles, and showcase humanity’s ability to adapt and innovate. As technology advances, future projects will likely push these boundaries further, creating even more ambitious and resilient subterranean routes.
