Yangcheng Evening News omni-media reporter Wang Danyang Pan Liang correspondent Cantonese intersection Xuanyue Road Jian Yang Xinhui
At 8 o’clock on June 11, the final joint of the world‘s longest and widest steel-shell concrete immersed tunnel – the deep-middle channel subsea tunnel was successfully launched, and it was precisely docked with the E24 pipe section on the east side. So far, the “Great Wall of the Sea” has officially closed, and Shenzhen and Zhongshan have “joined hands” at the bottom of Lingdingyang. The Shenzhong Channel has taken an important step towards the goal of opening to traffic in 2024.
The mating of the final joint is like “threading a needle under the sea”
The Shenzhen-Zhongshan Corridor is a core transportation hub project in the Guangdong-Hong Kong-Macao Greater Bay Area, with a total length of 24 kilometers, integrating “bridges, islands, tunnels, and underwater interconnections”. Among them, the subsea tunnel is about 6.8 kilometers long, including about 5 kilometers of immersed pipe sections, and consists of 32 pipe joints and 1 final joint.
Previously, 31 pipe joints have been lowered and connected in sequence from the east and west sides to the middle of the Shenzhong Passage Submarine Tunnel. On June 8, the last pipe section E23 and the final joint were shipped from the Guishan Island Immersed Pipe Prefabrication Plant in Zhuhai City and sailed to the construction waters. The final docking was completed on the 11th, which took nearly 70 hours.
The final docking of joints is like “threading a needle under the sea”, and the error must be controlled at the “millimeter level”. In order to achieve this difficult goal, the builders have gone through 2 years of technical demonstration and 1 year of joint design, and have pioneered a new technology for the overall prefabricated underwater push-out final joint of immersed tubes in the world.
At 14:00 on the 10th, the final joint pushing operation was ready, and under the action of the world‘s first dual system of “jack pushing + water pressure pushing”, it was slowly pushed out at a speed of 5 to 10 mm per minute. At 8 o’clock on the 11th, the final joint was precisely connected to the E24 pipe joint.
According to the person in charge of the CCCC No. 1 Harbor Engineering Bureau project responsible for the construction, during the launch of the final joint, the project team innovatively used the underwater binocular photography positioning technology and the underwater wire drawing technology. Through mutual review and joint calculation of the two, the final joint Installing the docking on the seafloor provides higher accuracy positioning data.
“Before the final joint butt joint construction, we have achieved the ‘millimeter-level’ plane installation accuracy of 15 pipe joints through the control system based on Beidou measurement.” Song Shenyou, chief engineer of the Shenzhen-China Channel Management Center, said. A series of innovative measures adopted by Helong of channel subsea immersed tube tunnel have enriched the “Chinese plan” and “Chinese standard” of the world‘s cross-sea immersed tube tunnel, and expanded my country’s leading edge in this field.
Consolidate my country’s leading level in the field of cross-sea cluster engineering
Located in the lower reaches of the Pearl River estuary and the geometric center of the Guangdong-Hong Kong-Macao Greater Bay Area, the Shenzhen-Zhongshan Corridor is the only direct road connection between the two major city groups of the “Shenguanhui” on the east bank of the Pearl River and the “Zhuzhong River” on the west bank. One of the most difficult cross-sea cluster projects, it is necessary to build the world‘s first two-way eight-lane steel shell-concrete immersed tube tunnel, the world‘s largest span full offshore suspension bridge, subject to shipping, flood control, water conservancy, airport aviation height limit, marine environment , navigation safety and other multiple factors, it is necessary to overcome the particularly complex construction environment and worldwide technical problems.
As the first batch of demonstration projects of the Ministry of Transport to create a century-old quality engineering, the Shenzhong Channel has also developed a number of world-first equipment and systems such as an immersed tube floating installation integrated ship, and developed a steel shell-concrete immersed tube tunnel design theory and reasonable structure. And many other international leading technologies, realized the millimeter-level installation of 15 pipe joints in the immersed tunnel under deep water conditions, the steel shell self-compacting concrete void detection pass rate was 100%, and the alignment control accuracy of the Lingdingyang Bridge was increased by 3 times compared with the specification requirements, etc. Outstanding results will form a complete set of technologies for the design and construction of cross-sea cluster projects with independent intellectual property rights, leading the high-quality development of the industry, and further consolidating China’s leading level in the field of cross-sea cluster engineering.
Accelerating the construction of a 100-kilometer “golden inner bay” around the Pearl River Estuary
The subsea tunnel has been closed, and the construction of the final joint and post-welding section will be carried out, and the tunnel will be completed in November; before this, the bridge project with a total length of 17.2 kilometers has been closed; The project has been fully launched, and it is striving to sprint towards the completion and opening to traffic of the project in 2024. After the project is completed and opened to traffic, the driving time between Shenzhen and Zhongshan will be reduced from the current 2 hours to about 20 minutes, and the Shenzhen-Zhongshan Passage will become a traffic artery connecting the urban agglomerations on the east and west banks of the Pearl River Estuary.
“The subsea tunnel of the Shenzhen-Zhongshan Passage was successfully closed, speeding up the construction of a 100-kilometer ‘Golden Inner Bay’ around the Pearl River Estuary.” Deng Xiaohua, Secretary of the Party Committee and Chairman of Guangdong Communications Group, said.
Editor: Zheng Jianlong