China News Service, Guangzhou, March 22 (Cai Minjieyue Road Construction) Guangdong Provincial Transportation Group announced on the 22nd that at 15:00 on the 21st, after nearly 27 hours of continuous operation, the core project of the Guangdong-Hong Kong-Macao Greater Bay Area deep-center channel immersed tube tunnel The eighth pipe section (E8) successfully realized the precise docking of 36 meters underwater. So far, the immersed tube tunnel of the island tunnel project of the project has been completed at 1278.5 meters, which is a quarter of the total length of the immersed tube section (5035 meters).
The E8 pipe joint installed this time is a standard pipe joint, with a length of 165 meters, a width of 46 meters, a height of 10.6 meters, and a weight of about 80,000 tons. The placement position is close to the deepest point on the entire line. The construction of the deep water tank is complicated and difficult.
"This is the first time that we have carried out geological compaction in the bedrock area. There is a risk of falling silt on the slope. At the same time, due to the unevenness and fissures of the rock mass, the safety risk of the leveler's pile insertion construction is high. In the face of challenges, we plan ahead and scientifically The deployment, safe and efficient completion of the basic processing work before the sinking of the immersed tube." said Ning Jinjin, the executive deputy chief engineer of the Shenzhen-Zhongshan Corridor Project Department of China Communications First Aviation Administration.
At 12:30 on March 20th, the world's first immersed, tube-transport-safety integrated vessel "One Sail Jinan 1" set sail from Guishan Island in Zhuhai, and floated the E8 pipe joint all the way north on a nearly 50-kilometer channel. On the 21st It crossed the alumite waterway for the first time at 0:30 in the morning.
This waterway is one of the busiest waterways in Lingdingyang, and there is a high risk of collisions when crossing at night. With the assistance of the Guangdong Maritime Safety Administration, a 30-minute closure control was carried out during the period. After reaching the sinking waters, night mooring operations were carried out.
At 7:15 am on March 21st, the E8 pipe section began to sink.
Different from the previous pipe joints, combined with comprehensive consideration of weather and hydrology, the E8 pipe joint is the first immersed pipe to choose daytime floatation, night mooring, and daytime docking. Personnel, equipment, and craftsmanship are all facing new challenges.
"Mainly because during the daytime docking coincides with the most active stage of the ionosphere, it is easy to cause signal instability or even loss of lock risk, which will adversely affect the control and installation accuracy of the pipe joints. During the operation, we introduced the Beidou positioning system to strengthen Measures such as monitoring and paying close attention to signal quality to ensure the smooth progress of the docking." Ning Jinjin explained.
At around 3 pm on the 21st, after nearly 27 hours of continuous operation, the E8 pipe section was successfully docked.
After penetration measurement, the butt joint deviation of E8 pipe section is within 50 mm, which meets the acceptance control standard.
The deep-to-medium passage is about 24 kilometers long and adopts the technical standards of a two-way 8-lane expressway with a design speed of 100 kilometers per hour. It is planned to be completed and opened to traffic in 2024.
The subsea tunnel is about 6.8 kilometers long, and the immersed pipe section is about 5 kilometers long. It adopts the steel shell concrete composite structure that is first applied in China and the first large-scale application in the world. It is composed of 32 pipe sections and 1 final joint. It is currently the world's largest Wide submarine immersed tube tunnel.
Song Shenyou, deputy director and chief engineer of the Shenzhen-Zhongshan Passage Management Center, said that the next step will be to prepare for the installation of the E9 pipe section. The installation depth of the pipe section is about 40 meters, which is the deepest installation water area on the whole line, and the construction is difficult.
According to the plan, the first pipe section on the east side of the project's immersed tube tunnel will be laid in August this year. This is the first super-wide and variable-width pipe section on the entire line, which is technically difficult.
The Shenzhen-China Corridor is a major project for the Guangdong-Hong Kong-Macao Greater Bay Area to implement the strategy of “speeding up transportation to a strong country” as a new start of the country’s 14th Five-Year Plan. After completion, it will effectively release the pressure on the existing road network and contribute to the improvement of the national highway network and The comprehensive transportation system in the Pearl River Delta region, promoting the industrial interconnection and the efficient allocation of various elements in the Guangdong-Hong Kong-Macao Greater Bay Area, and accelerating the integration and development of urban agglomerations in the Bay Area are of important strategic significance.
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