World’s longest tunnel to stretch 76 miles and cut 8-hour journey to 40 minutes | World | News

A ground-breaking undersea tunnel costing £20bn could cut an eight-hour journey to just 40 minutes.

The proposed Bohai Gorge Tunnel in China will cross multiple fault zones along its 123 km (76 mi) length, with planners vowing to use the latest earthquake-resistant technology to prevent disaster. The plan features longitudinal ventilation shafts to maintain air quality over enormous distances.

Additionally, there are numerous cross passages connecting two parallel tunnels designed to run approximately 80 m below the seabed. Engineers also incorporated several hundred emergency shelters needed for evacuations in a 123km tunnel where fire or flooding could be catastrophic.

The current estimated budget for the flagship scheme stands at £20bn, and although an exact completion date has not been confirmed, a Chinese government official stated in 2018 that officials were keen to start the project “as soon as possible”.

Once completed, the tunnel will dwarf all existing competitors. The 31-mile (49.6 km) Channel Tunnel was first designed during the Napoleonic Era, but was not completed until 1993. Japan’s 53.85-kilometer (33.5 mi) Seikan Tunnel currently holds the record for the world’s longest tunnel operating under a body of water, with a 23.3 km (14.5 mi) underwater section.

Trains in the Bohai Strait Tunnel are expected to reach speeds in excess of 150 miles per hour and travel time between the cities of Dalian and Yantai will be reduced by almost 90%. They will leave behind Eurostar trains, which can only reach speeds of 160 mph when passing through the Channel Tunnel.

A staggering 56 miles of the tunnel will remain under water, exceeding the combined length of the submerged section of the Channel Tunnel and the Seikan Tunnel.

This extraordinarily ambitious undertaking is expected to take 10 to 15 years to complete. By comparison, the Channel Tunnel took around six years to complete once construction began. The first train to pass through the tunnel is likely to make its journey in the late 2030s or later.

The cities at both ends of the tunnel are vital industrial powerhouses. Dalian has evolved from a major port into a leading financial, shipping and logistics center for East Asia.

Meanwhile, Yantai, traditionally known for fruit growing, has recently experienced significant expansion in petrochemical, automotive manufacturing, electronics, pharmaceuticals and high-tech sectors.

Currently the fastest connection between the two cities is the Bohai Train Ferry, which takes approximately eight hours to cross the strait.

By significantly reducing travel times between the two cities, Chinese officials hope to further boost their booming economic output. A government spokesman confirmed in 2018 that authorities were keen to implement the project “as soon as possible”. A tunnel under the Bohai Sea would transform transport links across China, Lu Dadao of the Chinese Academy of Sciences told reporters. They said: “Avoiding hubs in Beijing and Tianjin will ease the pressure on railways between Beijing and Tianjin, Beijing and Shanghai, and even Beijing and Guangzhou.”

Du Yanliang of the Chinese Academy of Engineering Sciences explained that the tunnel will also strengthen connections between the well-established industrial centers of the northeast, the Bohai economic region and the Yangtze delta region. However, the project did not remain without controversy; environmental campaigners say the area is teeming with wildlife, particularly serving as a vital habitat and breeding ground for the spotted seal, a Class II protected species.

Many areas within the proposed construction area have been reserved as potential areas for nature reserves.

Sun Fenghua of the Chinese Academy of Sciences stressed the need for “serious research on all issues related to tunnel construction… We should not proceed until these questions are fully understood.”