The steel behemoth begins digging! The world's longest undersea road tunnel begins shield tunneling operations

On December 30, as the cutterhead of the "Haitian" shield machine slowly turned, the world's largest submarine highway tunnel, the Qingdao Jiaozhou Bay Second Tunnel, officially started shield tunneling operations.

This move means that the main body of the world's largest and longest submarine road tunnel has officially started shield tunneling operations.

This is a photo taken at the construction site of the southern main tunnel of the Qingdao Jiaozhou Bay Second Tunnel Project, showing the Haitian shield machine at its starting position (photo taken on December 30). Xinhua News Agency reporter Li Ziheng

Digging a tunnel 95 meters below the sea is equivalent to a fingernail bearing 12 kilograms of pressure . How will the "cross-sea journey" through Jiaozhou Bay begin?

It is understood that the tunnel geology is mainly granite and diabase, with well-developed rock joints and fissures, and multiple fracture zones. The construction geology is complex and the construction risk is high, which is the key control line for the entire tunnel construction period. The "Haitian" shield machine enters the sea as soon as it starts, and needs to cross complex and changeable, uneven hardness and fracture zone strata for a long distance.

According to the different geological and construction environments, the sea section adopts the layout of "two main line tunnels + intermediate service tunnel", and is designed to use a combination of drilling and blasting and shield methods to cross the Jiaozhou Bay.

This time, the shield machine will dig from the Qingdao Port terminal to the west coast, connect with the drill and blast section tunnel, and be received and disassembled in the seabed cavern.

Observing from the cross-sectional diagram of the project, the project presents three "pipelines". The "pipelines" on both sides are round-trip tunnels. Each pipeline is divided into three layers: "smoke exhaust layer", "driving layer" and "corridor layer", of which the "driving layer" has three lanes. The service tunnel is sandwiched between the "pipelines" on both sides, which is similar to the service station setting on a highway.

On December 30, builders were working at the shield tunneling site of the southern main line tunnel of the Qingdao Jiaozhou Bay Second Tunnel Project. Photo by Xinhua News Agency reporter Li Ziheng

Many netizens said: This is a science fiction movie reflected in reality!

The Qingdao Jiaozhou Bay Second Tunnel connects the main urban area of ​​Qingdao and the national-level new area Qingdao West Coast New Area, with a designed speed of 80 kilometers per hour. The total length of the project is 17.48 kilometers, of which the main line tunnel is 14.37 kilometers long, including a 9.95-kilometer sea section, and is scheduled to be completed and opened to traffic by the end of 2027. The tunnel has the function of a cross-sea channel for passenger and freight vehicles, with a designed service life of 100 years and a designed speed of 80 kilometers per hour.

Previously, on June 30, the shield section of the Jiaozhou Bay Second Tunnel Project began excavation construction, starting the "cross-sea journey" across the Jiaozhou Bay.

On June 30, a worker monitored and maintained the operation of the shield machine in the service tunnel. Photo by Xinhua News Agency reporter Li Ziheng

This is not only a grand project, but also a practice of scientific and technological innovation. It will promote the development of China's undersea tunnel construction technology and provide valuable experience and technical support for future undersea tunnel projects!

Comprehensive sources: Xinhua News Agency, China Science and Technology Network, etc.