舟山联通陆地将添世界最长海底双向六车道高速公路隧道

Core Viewpoint - The approval of the feasibility study report for the Ningbo Qijia Mountain to Zhoushan Jintang section of the Ningbo-Zhoushan Expressway double line marks a significant step forward for the construction of the world's longest underwater dual-direction six-lane highway tunnel, indicating that the second channel of the Ningbo-Zhoushan Expressway will commence full construction [1][3]. Group 1: Project Overview - The total investment for the Ningbo-Zhoushan Expressway double line is approximately 31.4 billion yuan, with a total length of about 46 kilometers, designed to a dual-direction six-lane highway standard and an overall design speed of 100 km/h [3]. - The project consists of three segments, with the Jintang to Dasha segment (rail and road combined bridge) costing about 10.9 billion yuan and expected to be completed by 2028, the Ningbo Qijia Mountain to Zhoushan Jintang segment (underwater tunnel) costing about 15.7 billion yuan and expected to be completed by 2030, and the Beilun Haosifang to Qijia Mountain segment costing about 4.8 billion yuan and expected to be completed by 2029 [3]. Group 2: Technical Details - The approved section of the Ningbo-Zhoushan Expressway double line is 18.1 kilometers long, featuring the world's longest underwater dual-direction six-lane highway tunnel, the Jintang Underwater Tunnel, which is 11.6 kilometers long and utilizes 16-meter shield tunneling technology [3]. - The construction of the tunnel presents significant technical challenges, including "super large, super long, super deep" characteristics, complex geological conditions, underwater precision alignment, and underwater tunnel dismantling [3]. Group 3: Strategic Importance - The construction of this project is crucial for improving the national highway network, promoting high-quality development in Zhejiang, accelerating the construction of the Yangtze River Delta urban agglomeration, and enhancing the transportation and emergency response capabilities of the Ningbo-Zhoushan cross-sea passage [4]. - Once the double line is fully completed, the total length of the Zhoushan connected island expressway will reach 120 kilometers, further solidifying its status as China's longest connected island expressway [4].