Deep-sea Space Station

On February 6, China's first domestically developed shielded saturation pressurized cabin entry equipment, the "Deep-sea Space Station," successfully completed its inaugural engineering application at the Ningbo-side construction site of the Jintang Undersea Tunnel of the Ningbo-Zhoushan Railway. Operating in a high-pressure environment at a depth of 75 meters, it carried out shielded cabin entry operations and replaced a total of 46 cutter tools. This achievement effectively breaks through the traditional technical limitation of a safe operational depth of 60 meters, adding a core technological accomplishment to China's deep-buried tunnel construction sector.
Reportedly, the "Deep-sea Space Station" was jointly developed by China Railway 14th Bureau Group Co., Ltd. and the Shanghai Salvage Bureau under the Ministry of Transport. After three years of technological breakthroughs and equipment commissioning, it comprises multiple functional modules, including the Ninghai (Living) Cabin, Tanhai (Shuttle) Cabin, and Zhenhai (Control) Cabin. Innovatively integrating mature saturation diving technology from marine engineering with shielded tunnel construction techniques, the equipment effectively overcomes the technical bottlenecks of traditional pressurized cabin entry operations for shielded tunneling. It achieves breakthroughs in three core dimensions: operational depth, construction efficiency, and safety assurance, filling the technological gap in shielded pressurized cabin entry for deep-buried tunnels in China.

Ninghai (Living) Cabin

Tanhai (Shuttle) Cabin

Zhenhai (Control) Cabin

In terms of technological breakthroughs:
Operational Depth: The "Deep-sea Space Station" has a designed maximum operational depth of 100 meters. Its actual application depth reached 75 meters, significantly surpassing the traditional 60-meter operational limit and precisely meeting the construction requirements of the Jintang Undersea Tunnel, which has a maximum burial depth of 78 meters.
Construction Efficiency: The equipment extends the traditional single effective pressurized cabin entry duration from 40 minutes to 8 hours. It supports 24-hour cyclic operations by multiple teams of workers, with a maximum continuous operational cycle of 28 days, substantially enhancing the efficiency of shielded tunneling for deep-buried tunnels.
Safety Assurance: Through the accompanying "Ninghai Cabin," workers can reside and operate for extended periods in high-pressure environments. This effectively mitigates occupational health risks such as nitrogen narcosis and decompression sickness caused by frequent pressurization and depressurization, comprehensively reinforcing construction safety measures.
As a critical control project of the Ningbo-Zhoushan Railway, the Jintang Undersea Tunnel is currently the world's longest, geologically most complex, and most challenging deep-sea high-speed railway tunnel, with a maximum burial depth of 78 meters. During shielded tunneling, it faces technical challenges such as frequent cutter wear and significant high-pressure operational risks. The successful application of the "Deep-sea Space Station" has completely eliminated the core technical obstacles in the tunnel's construction.
As of now, the "Ningbo-Zhoushan" shield machine responsible for tunneling on the Ningbo side has advanced over 3,000 meters. It is projected to achieve precise docking of the undersea tunnel by the end of 2026, laying a solid foundation for the full opening of the Ningbo-Zhoushan Railway.