甬舟铁路金塘海底隧道西起浙江宁波市北仑区，东至舟山市金塘镇，全长16.18公里，是世界最长 海底高铁隧道。隧道采用两台大直径盾构机——"定海号"与"甬舟号"，分别从舟山、宁波两侧同步始 发、相向掘进，计划2026年在海底复杂地层中实现高精度对接。 素材来源：中铁十一局城轨公司融媒体中心 【纠错】 【责任编辑:薛涛】 记者：黄宗治 ...

Core Insights - The construction of the world's longest underwater high-speed rail tunnel has achieved a significant milestone with the "Dinghai" shield machine surpassing 5,000 meters of excavation, marking approximately 80% completion of the Zhoushan side of the tunnel, which is 6,270 meters long [1][3] Group 1: Project Overview - The Jintang Underwater Tunnel is a key project of the Ningbo-Zhoushan Railway, spanning 16.18 kilometers, with the shield section measuring 11.21 kilometers [3] - Two large-diameter shield machines, "Dinghai" and "Yongzhou," are being used for excavation from both sides, facing complex geological conditions including high water pressure and various soil types [3] Group 2: Construction Challenges - The geological conditions are extremely complex, requiring the shield section to navigate through hard rock, clay, and sandy layers, presenting multiple challenges such as high intensity, high water pressure, and high precision [3] - The construction team has implemented measures such as enhanced tail seal management, optimized excavation parameters, and real-time monitoring to control ground disturbance and ensure safety [3] Group 3: Future Plans - The "Dinghai" shield machine is set to continue its progress towards the seabed connection point, with the "Yongzhou" shield machine also advancing steadily [5] - The project is expected to achieve a successful underwater connection by October 2026, with the Ningbo-Zhoushan Railway projected to be operational by 2028, integrating Zhoushan into the national railway network [5]

Core Insights - The "Yongzhou" shield machine has achieved over half of its tunneling progress for the world's longest underwater high-speed rail tunnel, marking a significant milestone in the construction of the Ningbo-Zhoushan railway [1][3]. Group 1: Project Overview - The Jintang underwater tunnel is a key project of the Yongzhou railway, stretching 16.18 kilometers, with the shield section measuring 11.21 kilometers [3]. - The tunnel employs two shield machines, "Yongzhou" and "Dinghai," which are advancing simultaneously from both Ningbo and Zhoushan sides [3]. Group 2: Technical Challenges - The geological conditions along the Jintang underwater tunnel are extremely complex, requiring the crossing of various risk sources such as sea dikes, docks, and shipping lanes [4]. - The maximum depth of the underwater section reaches 78 meters, with a maximum water pressure of 8.4 bar, equivalent to nearly 1 ton of weight on an adult's palm [4]. - The Ningbo side has experienced frequent geological changes, necessitating high-pressure tool changes, with the "Yongzhou" machine completing 12 geological transitions and changing tools over 2400 times [4]. Group 3: Strategic Importance - The Yongzhou railway is a major project in China's Medium- and Long-term Railway Network Plan (2016-2030), with a total length of 76.4 kilometers and a design speed of 250 kilometers per hour [4]. - Once operational, the project will connect Zhoushan, the only city in the Yangtze River Delta without a railway, to the national railway network, significantly enhancing regional integration and development [4].