Core Points - The Ningbo-Zhoushan Railway's underwater tunnel, known as the Jintang Submarine Tunnel, is a record-breaking engineering project, measuring 16.18 kilometers in total length, with an underwater section of 11.21 kilometers, making it the world's longest underwater high-speed rail tunnel [1][5] - The construction employs two shield machines that start from both Ningbo and Zhoushan sides, facing each other to ensure precise alignment after traversing complex geological conditions [1][2] - The project is significant for the integration of the Yangtze River Delta region, as it will end the historical lack of railway access to Zhoushan upon completion [5] Construction Details - As of May 2024, the shield machine has advanced nearly 2,400 meters, currently located about 65 meters below sea level, marking a critical phase as it transitions from land to marine construction [2] - The shield machine must navigate through various geological layers, including four soft soil sections and eight hard rock sections, with hard rock layers comprising nearly 70% of the total [2][4] - Advanced technologies, such as a proactive geological forecasting system, are utilized to monitor geological conditions ahead of the shield machine, enhancing safety and efficiency [4] Workforce and Timeline - The project employs over 200 workers who operate in two shifts around the clock, with the tunnel expected to connect with the Zhoushan side by the end of 2026 [5] - The project is positioned as a key initiative within China's 14th Five-Year Plan, emphasizing the urgency and commitment to high-quality project execution [5]

Core Points - The Ningbo-Zhoushan Railway's underwater tunnel, known as the Jintang Submarine Tunnel, is a record-breaking engineering project, measuring 16.18 kilometers in total length, with an underwater section of 11.21 kilometers and a maximum depth of 78 meters, making it the world's longest underwater high-speed rail tunnel [2][3] - The construction employs two shield machines that start from both Ningbo and Zhoushan sides, advancing towards each other while navigating high water pressure and complex geological conditions [2] - The project is significant for the integration of the Yangtze River Delta region, as it will end the historical lack of railway access to Zhoushan upon completion in late 2026 [7] Construction Details - As of May 2024, the shield machine has advanced nearly 2,400 meters, currently located about 65 meters below sea level, marking a critical phase as it transitions from land to marine construction [3] - The shield machine must traverse various geological layers, including 4 segments of soft soil and 8 segments of hard rock, with hard rock layers comprising nearly 70% of the total [3] - Advanced technologies, such as a proactive geological forecasting system, are utilized to enhance the precision of geological assessments and improve construction safety [5] Workforce and Project Management - The project employs over 200 workers who operate in two shifts around the clock to ensure continuous progress [7] - The project team is committed to maintaining high-quality standards and timely completion, aligning with the goals of the 14th Five-Year Plan [7]

Core Points - The Ningbo-Zhoushan Railway's Jintang underwater tunnel is a record-breaking engineering project, measuring 16.18 kilometers in total length, with an underwater section of 11.21 kilometers and a maximum depth of 78 meters, making it the world's longest underwater high-speed rail tunnel [1][2] - The construction employs two shield machines that start from both Ningbo and Zhoushan sides, facing complex geological conditions, including high water pressure and various soil types [1][2] - The project utilizes advanced technologies, such as a proactive geological forecasting system, to enhance construction efficiency and safety [3] Group 1 - The Jintang underwater tunnel is a key project for the Ningbo-Zhoushan Railway, with significant implications for regional connectivity and economic development [1][3] - The shield machine, named "Yongzhou," has already progressed nearly 2400 meters since its launch in May 2024, marking a critical milestone as it transitions from land to underwater construction [2] - The project team has designed the shield machine's cutter head to withstand the challenges posed by alternating soft and hard soil layers, which constitute nearly 70% of the tunnel's path [2][3] Group 2 - The construction site employs over 200 workers who operate in two shifts around the clock, aiming for high-quality and timely project completion by the end of 2026 [3] - The successful completion of the Jintang underwater tunnel will end the historical lack of railway connectivity to Zhoushan, contributing to the high-quality integration of the Yangtze River Delta region [3]

Core Viewpoint - The successful crossing of the "Yongzhou" shield machine into the marine section marks the commencement of the underwater construction phase of the world's longest underwater high-speed rail tunnel, the Jintang Undersea Tunnel, which is a critical project for the Yongzhou Railway [1] Group 1: Project Overview - The Jintang Undersea Tunnel is located beneath the Jintang Waterway, connecting Ningbo and Zhoushan, with a total length of 16.18 kilometers [1] - The shield section of the tunnel measures 11.21 kilometers, making it the longest underwater high-speed rail tunnel in the world [1] Group 2: Construction Milestone - The shield machine successfully traversed the seawall, transitioning from land to marine excavation, indicating significant progress in the construction timeline [1]