After 17 hours of continuous construction work, the first section of Dalian Bay Subsea Tunnel, the first large cross-harbor immersed tube tunnel project in North China, was successfully sunk into the sea on December 9, 2020, precisely connecting with the buried tunnel section on the north bank, which marks a significant breakthrough in the construction of the first immersed tube tunnel in cold regions of China.
Special
construction ships "Jin'an No.2" and "Jin'an No.3" are towing
Section E1 of the immersed tube and sailing (shot by Yang Yi)
The tunnel is 5.1 km long in total and consists of 18 sections of immersed tube. The Section E1 of the immersed tube which was installed this time is a non-standard section, 135 meters in length, 33.4 meters in width, 9.7 meters in height and 41,000 tons in weight.
The green-marked
line indicates the location of Dalian Bay Cross-harbor Subsea Tunnel
Special
construction ships "Jin’an 2" and "Jin’an 3" are towing the
Section E1 of the immersed tube and sailing (shot by Yang Yi)
Towed by 6 tugs, China's first group of construction ships "Jin'an 2" and "Jin'an 3" which are specialized for floating transportation and installation of immersed tube, were towing Section E1 and setting sail on time at 10:30 am on December 8.
By two changes of course, the ships successfully arrived at the mooring area at 13:29 am, and the mooring works were started then. At 21:20, all the preparatory works for sinking and placing immersed tube were all set. At 3:45 am on December 9th, the first section of the immersed tube was precisely joined to the existing buried tunnel section on the north bank.
On December 8,
the preparation works for sinking the immersed tube were completed (shot by Yang
Yi)
“The Dalian Bay Subsea Tunnel Project is the subsea tunnel project of highest latitude in China at present. Because of the cold weather in the north, stricter requirements have been set for the frost resistance of concrete.” said Zhang Haiying, the chief engineer from General Management Department of the Dalian Bay Subsea Tunnel Project of CCCC, “Meanwhile, compared with the construction of Hong Kong-Zhuhai-Macao Bridge, due to the limitation of the submarine topography and traffic diversion of Dalian Bay, the docking area is narrow and the turning circle is small, therefore, stricter requirements for the prefabrication and installation of immersed tubes are implemented.”
In order to ensure the installation of the immersed tube section and its perfect joint to the existing buried tunnel section, the R&D team has been spending three years to tackle key problems, initiate 25 scientific research projects, complete 140 special construction method statements and overcome a number of technical problems, and eventually realized the precise joint between the first section of the immersed tube and the buried tunnel section of the north bank.
It is known that after the completion of the project, it will be a fast passage for Dalian City running South and North, which is of great significance to ease traffic congestion in the central urban area of Dalian, expand urban development space, and promote the integration of the two sides of Dalian Bay.
