Zhoushan Side of Jintang Subsea Tunnel on Ningbo-Zhoushan Railway Completes 6,270 Meters of Shield Tunneling

en.Wedoany.com Reported - On November 11, shield tunneling on the Zhoushan side of the Jintang Subsea Tunnel of the Ningbo-Zhoushan Railway was completed. The "Dinghai" extra-large-diameter shield tunneling machine responsible for this section achieved a cumulative excavation of 6,270 meters, becoming the first to reach the designated subsea breakthrough position. The project is constructed by Shanghai Guotie Construction Management Company and undertaken by China Railway 11th Bureau Group. With the tunneling task on the Zhoushan side now complete, the shield machine on the Ningbo side will continue advancing toward the subsea breakthrough position.

The Jintang Subsea Tunnel is a controlling project of the entire Ningbo-Zhoushan Railway line, spanning the Jintang Waterway between Ningbo City and Zhoushan City in Zhejiang Province. The tunnel has a total length of 16.18 kilometers, of which the shield-tunneled section is 11.21 kilometers. The project uses two extra-large-diameter shield machines tunneling toward each other, with the "Dinghai" undertaking the 6,270-meter task on the Zhoushan side and the "Yongzhou" handling the tunneling task on the Ningbo side, ultimately achieving high-precision breakthrough under the sea.

The Zhoushan-side tunnel section completed in this excavation has a maximum burial depth of approximately 80 meters. The construction area features complex strata with alternating soft soil, silty sand, and hard rock, with the highest hard rock strength approaching 200 MPa. During advancement, the shield machine must cope with frequent stratum changes, high water pressure, and long-distance continuous equipment operation, placing high demands on cutterhead cutting capability, shield attitude control, segment assembly, and construction surveying.

During construction, China Railway 11th Bureau Group relied on an intelligent construction management platform for large-diameter shield tunnels and a digital twin system to conduct dynamic monitoring of shield equipment operating status, cutterhead attitude, and stratum changes, and used remote diagnostics and data analysis to assist in adjusting tunneling parameters. For cutter inspection and replacement operations under high subsea water pressure, the construction team also adopted specialized pressurized working equipment to ensure continuous advancement of the shield machine under complex geological conditions.

Shield tunneling on the Ningbo side has currently completed approximately 89%, and the two shield machines are expected to achieve breakthrough under the sea in 2027. After the "Dinghai" on the Zhoushan side reaches the designated breakthrough position, equipment attitude locking, measurement verification, and in-tunnel disassembly preparations will still be required, while the Ningbo side continues to advance the remaining tunneling task. After the two sides break through, the project will still need to carry out subsequent tunnel construction and related supporting works.

The main line of the Ningbo-Zhoushan Railway is approximately 76.4 kilometers long with a design speed of 250 kilometers per hour. The line connects Ningbo and Zhoushan, and upon completion will end the history of Zhoushan City having no railway service. After the project enters operation, the railway travel time from Ningbo to Zhoushan is expected to be shortened to approximately 30 minutes, forming a new railway corridor in the coastal area of the Yangtze River Delta.