Core Viewpoint - The article emphasizes the importance of developing advanced technologies and "national heavy equipment" during the "14th Five-Year Plan" period, highlighting significant achievements in China's engineering capabilities, particularly in the field of shield tunneling machines [1][20]. Group 1: Technological Advancements - The "Jiang Hai" shield tunneling machine, with a maximum excavation diameter of 16.64 meters, is custom-built for the Hai Tai Yangtze River Tunnel project, which is a key national infrastructure initiative [5][11]. - The Hai Tai Yangtze River Tunnel will significantly reduce travel time across the river from one hour to ten minutes, showcasing the efficiency of modern engineering [5]. - The "Jiang Hai" machine incorporates advanced technologies such as a real-time monitoring system and intelligent assembly robots, making it a highly automated and digitalized piece of equipment [16][20]. Group 2: Engineering Challenges - The "Jiang Hai" machine faces significant challenges, including high water pressure and deep excavation, requiring innovative solutions like the development of a constant pressure tool replacement technology [15][14]. - The machine's main bearing, considered its "heart," is designed for a lifespan of over 20,000 hours, reflecting the rigorous engineering standards required for such a project [14][12]. - The construction process demands precise control of ground disturbance, with tolerances maintained at the millimeter level to avoid damaging the surrounding soil [15]. Group 3: Industry Growth and Market Position - China's shield tunneling machine industry has achieved a global market share of 70%, with products exported to over 40 countries and regions [20]. - The period of the "14th Five-Year Plan" has seen rapid growth in the number and technological sophistication of ultra-large diameter shield machines, indicating a shift from reliance on foreign technology to domestic innovation [22][20]. - The industry is expanding its application scenarios beyond traditional uses, venturing into energy channels and complex tunneling directions, demonstrating the versatility and advancement of Chinese engineering [23][22].

Core Viewpoint - The article emphasizes the importance of developing "national heavy equipment" as a key strategy for China to achieve high-level technological self-reliance and leadership in new productive forces during the "14th Five-Year Plan" period and beyond [1]. Group 1: Development of "National Heavy Equipment" - The "Jianghai" shield tunneling machine, developed by China Railway 14th Bureau and China Railway Construction Heavy Industry Group, has a maximum excavation diameter of 16.64 meters and is specifically customized for the Haitai Yangtze River Tunnel project [2][3]. - The Haitai Yangtze River Tunnel, which connects the Haimen District of Nantong and Taicang City of Suzhou, is 11.185 kilometers long, with the shield tunnel section measuring 9,315 meters, making it the world's longest underwater highway shield tunnel [2][7]. - The construction of the tunnel will reduce the travel time across the river from one hour to just ten minutes, utilizing a dual six-lane design with a speed limit of 100 kilometers per hour [2][3]. Group 2: Technical Innovations and Challenges - The "Jianghai" shield machine incorporates advanced technologies, including a real-time monitoring system for the main bearing and an intelligent assembly robot for segment components, showcasing a high level of automation and digitalization [5][6]. - The machine faces significant challenges, such as high water pressure and deep burial, with the maximum depth reaching 75 meters and water pressure exceeding 7.5 bar, complicating the replacement of worn-out cutting tools [4][5]. - To address the challenge of tool replacement under high pressure, the development team innovated a constant pressure tool replacement technology, which includes a high-pressure gate for each replaceable tool [5]. Group 3: Industry Growth and Global Position - China's shield tunneling machine industry has achieved a global market share of 70%, with products exported to over 40 countries and regions across five continents [7]. - The "14th Five-Year Plan" period has seen rapid growth in the production and application of ultra-large diameter shield machines, with advancements in technology and an expansion of application scenarios [7][8]. - The industry is moving towards greater excavation diameters, faster tunneling speeds, deeper excavation depths, and more diverse application scenarios, indicating a commitment to continuous innovation and leadership in the field [8].