How can an undersea tunnel built between two places “run in both directions”?

From Ningbo to Zhoushan, a project is under construction. Diving into the seabed, a tunnel gradually extends. Above the sea, some people are on a boat, watching the waves and looking up at the footprints of flying birds; under the sea, some people are on a car, enjoying the speed of the wind and traveling with marine life. The Jintang Undersea Tunnel is a controlling project of the entire Ningbo-Zhoushan Railway in Zhejiang Province. Its construction will end the history of Zhoushan without a railway and will also bring a "new" experience to people's travel.

Construction towards each other, docking in the sea, dismantling in the tunnel, and two-way excavation between the two places, you and I are all witnesses of this "two-way rush" construction project.

(Photo provided by China Railway 14th Bureau Ningbo-Zhoushan Railway Project Department)

The Jintang Undersea Tunnel of the Ningbo-Zhoushan Railway is 16.18 kilometers long, including 11.2 kilometers of shield tunnel. In this regard, some people asked, "Why build such a long undersea tunnel?" In order to avoid the impact of islands and other buildings on the waterway and surrounding areas, at the beginning of the construction of the tunnel, the construction team went through a long discussion: should we build a bridge or a tunnel? If we build a bridge, considering the impact on the shipping and waterways of the two sides of Ningbo and Zhoushan, we finally chose to start the construction with the tunnel under the tunnel.

In view of the engineering difficulties and project characteristics, the designers and the early creative team came up with the solution of "starting from both sides and connecting in the middle". The "Yongzhou" shield machine starts from Ningbo to Zhoushan; the "Dinghai" shield machine starts from Zhoushan to Ningbo. On May 16, 2024, the starting ceremony was held, officially opening the construction of the Jintang Undersea Tunnel, and a shocking "two-way rush" journey began.

(Photo provided by China Railway 14th Bureau Ningbo-Zhoushan Railway Project Department)

Under the huge body of the "Yongzhou" shield machine, the painted dragon pattern comes into view, implying the auspicious and safe crossing of the sea by the dragon. This is the expectation of the designers and also a good wish. In order to cope with the difficulties in the construction process, the team gave the "Yongzhou" shield machine a targeted design. First of all, "efforts" were made on the cutter of the shield machine. In order to cope with the complex geological environment, the cutter material of the shield machine was specially treated to be thick and strong. The design of the cutter also provides a guarantee for the construction of the submarine tunnel. As the "ear" of the shield machine, the advanced geological prediction system can clearly perceive the strata and obstacles ahead through the reflection of waves, which facilitates the clear detection of submarine mountains and makes the construction more accurate.

The tunnel construction site is very clean and tidy. The construction team has adopted the new concept of turning the construction site into a factory, and has also applied more high-tech means and a smart management and control platform to achieve control.

Hu Hao, an engineer of the Ningbo-Zhoushan Railway Project of China Railway 14th Bureau Group, said: "The smart control platform combines our personnel management, safety management, environmental management and digital shield platforms. It is precisely because of the intervention of the smart control platform that our tunnel construction has become less manned and unmanned, and it has also led us to a new step towards mechanization, digitization and intelligence. This platform also realizes our remote control function, and transfers some of the control in our daily operations to this platform."

(Photo provided by China Railway 14th Bureau Ningbo-Zhoushan Railway Project Department)

In the past, a boat ticket could take us to explore the sea, but in the future, a high-speed train will take us "across the sea". We can watch the waves rolling and seagulls flying; we can also enter the "tunnel" in the sea, ride the "sea" train, feel the power of technology, and go to more places we want to go.