On the afternoon of April 12, aboard the drilling vessel "Rongyang 288", as the last drilling casing was retrieved from the undulating sea surface, the offshore exploration for the Hangzhou Bay Sea-Crossing Bridge of the Nantong-Suzhou-Jiaxing-Ningbo Railway, for which China Railway Design Corporation (CRDC) is responsible for overall design, was successfully completed, laying a solid foundation for the project's preliminary design work. The Hangzhou Bay Sea-Crossing Bridge is 29.2 kilometers long and designed for a speed of 350 kilometers per hour. Once completed, it will become the world's longest and highest-standard high-speed railway sea-crossing bridge.
According to Zhang Peng, head of the geological specialty at CRDC: "The offshore exploration for the Hangzhou Bay Sea-Crossing Bridge took 5 months, completed 2.5 months ahead of schedule. The sea has strong winds and high waves, with rapid tides and currents; wind speeds can reach 40 meters per second, equivalent to a Category 13 gale, waves are nearly 7 meters high, and seawater flow velocity is nearly 5 meters per second. The upper marine silt layer is 20 to 40 meters thick, and the seabed stability is poor. Offshore exploration involves great risks and challenges, and is extremely difficult."
To overcome the difficulties and low success rate of conventional offshore drilling methods, the geological exploration team, after multiple field explorations and technical demonstrations, innovatively developed a needle-shaped hard alloy rib-type follow-up casing drilling technique, which can effectively overcome the effects of waves and thick silt layers, avoid seabed collapse and borehole collapse accidents caused by shallow gas blowouts, and increase the success rate of a single drilling from 60% to over 90%.
Zhang Jian, chief engineer of the Nantong-Suzhou-Jiaxing-Ningbo Railway project at CRDC, introduced that the Hangzhou Bay Sea-Crossing Bridge is designed with ballastless track and includes three navigation channel bridges (north, middle, and south) and approach bridges in the sea, shallow water, and shoal areas. It is an ultra-long high-speed railway bridge cluster project that will set multiple world records and is of milestone significance to the world's railway bridges and even the bridge engineering field.
"In the design of the Hangzhou Bay Sea-Crossing Bridge, we also carried out research and design for the full life cycle of multiple systems, including evacuation and rescue, operation and maintenance, and four-electric integration for ultra-long sea-crossing railway bridges, accumulating engineering experience for subsequent sea-crossing railway projects," said Zhang Jian.
The Nantong-Suzhou-Jiaxing-Ningbo Railway is part of the coastal corridor of the medium- and long-term railway network, designed for a speed of 350 kilometers per hour. The project starts at Nantong West Station in Nantong City, crosses the Yangtze River, passes through Suzhou and Jiaxing cities, crosses Hangzhou Bay, and enters the Ningbo hub via Cixi City. The total operating length of the main line is 310 kilometers, with 10 stations: Nantong West, Zhangjiagang, Changshu West, Suzhou North, Fenhu, Jiaxing North, Jiaxing South, Haiyan West, Cixi, and Zhuangqiao.
Once completed, the Nantong-Suzhou-Jiaxing-Ningbo Railway will accelerate the improvement of the Yangtze River Delta rail transit network system, greatly shorten the space-time distance from Ningbo to Shanghai, Suzhou, Beijing, and other places, further guide regional coordinated development, become a new engine for the development of the Yangtze River Delta region, and inject surging momentum into the development of the Yangtze River Economic Belt and the integrated development of the Yangtze River Delta region.