China News Service, Guangzhou, November 1 (Cai Minjie Yuelu Construction) Guangdong Provincial Transportation Group announced on the evening of the 31st that after about 27.5 hours of operation, the ultra-wide and variable-width tube section (E30) of the deep-medium channel immersed tube tunnel was completed accurately Docking.
So far, 16 pipe joints have been successfully installed in the deep-medium channel, and more than half of the installation and construction tasks of 32 immersed pipes have been completed. The length of the immersed pipe tunnel is 2475.2 meters.
The deep-medium channel subsea tunnel is about 6.8 kilometers long, and the immersed pipe section is about 5 kilometers long. It consists of 32 pipe sections and 1 final joint. It is the widest steel shell concrete subsea immersed tube tunnel in the world.
The project tunnel is connected to the east artificial island on the Shenzhen side of the underwater interchange. From the E27 pipe section to the E32 pipe section, the width of the tunnel gradually widens from two-way eight lanes to two-way ten lanes. Among them, the E30 pipe section has the largest change in the width of the immersed pipe (ie The section with the largest curvature change) has a width change of close to 4 meters, which is easily affected by water flow and produces obvious asymmetric effects. It is difficult to install by floating and sinking. It was developed by Poly Grow and Guangzhou Salvage Bureau Consortium Deep and Medium Channel Project S08 contract Section undertook to build.
The maximum variable-curvature pipe section E30 of the deep-medium channel is submerged and butt-joined.
Photo courtesy of Guangdong Transportation Group
In the early morning of October 30th, starting from Guangzhou’s South Salon Cave, the E30 tube section was led by a towing formation with a total horsepower of over 40,000 horsepower to ride the wind and waves to the Shenzhen side tunnel site.
In order to ensure the progress of the node as planned, the construction team of the Guangzhou Salvage Bureau coordinated with the Guangdong Maritime Department, the National Marine Environmental Forecasting Center, the Tianjin Water Transport Engineering Research Institute and other units to overcome the adverse effects of complex weather, select the operating window, and set up Multiple sets of floating installation plans lay a solid foundation for the docking of immersed pipes.
"The floating distance is about 20 kilometers long. It crosses the Lingding Channel and Blumstone Channel, the busiest waterway of the Pearl River Estuary, and has high navigable safety risks." said Kong Weida, project manager of the S08 contract section of the Guangzhou Salvage Bureau. The number of submerged installation pipe joints has increased, and the distance between the submerged docking area of the subsequent pipe joints to be installed and each channel is gradually shortened, and the shortest point is only 100 meters.
"The nearby waterways are intertwined and high-speed passenger ships travel frequently. The huge sailing waves produced by them will affect the docking stability of the immersed pipe and greatly increase the risk of construction operations. For the E30 pipe joint, this effect will be more obvious."
To this end, the construction team has set up a number of guard ships around the pipe joints, and announced in advance with the Guangdong maritime department and high-speed passenger ships. The on-site marine cruise ship will direct the ships to avoid and slow down when passing through the pipe joints to ensure construction safety.
On October 30, it experienced 8 channel changes, 4 tube turns and 1 round turn operation. Without disturbing the normal operation of water transportation, the towing formation firmly controlled the tube joints under the impact of strong winds and upstream currents. , The E30 pipe section weighing 65,000 tons was successfully transported to the tunnel site, and the pipe section was moored and twisted into place.
On the afternoon of October 31, after fine-tuning the sinking, pulling and hydraulic crimping processes, the E30 pipe section of the deep and medium channel successfully completed the docking installation.
At 7 o'clock in the evening, after the tripartite joint penetration measurement, the accuracy of the pipe joint butt meets the acceptance evaluation standard, and the work efficiency has been improved.
The E30 pipe section is the third pipe section with an ultra-wide, variable-width asymmetric structure on the curved axis of the project's immersed tube tunnel. The section width gradually widens from 49.75 meters to 53.5 meters, making prefabrication difficult.
"We use self-developed intelligent pouring equipment and systems, and on the basis of ensuring the quality and completing the pouring work of E32 and E31 two ultra-wide and variable-width pipe sections in advance, we continue to strive for perfection and improve pouring efficiency. Compared with the past, E30 pipe section pouring The construction period was shortened to 32 days, and the speed of "one pipe joint pouring in one month" was realized, and the pass rate of self-compacting concrete was 100%, which improved the quality of pipe joint prefabrication." Su Zongxian, chief engineer of the S08 contract section of the Poly Long Shenzhong Passage Project say.
At present, the construction of the Shenzhen-China Corridor is progressing steadily.
The Lingdingyang Bridge and Zhongshan Bridge have been transferred to the superstructure construction stage, the construction of the east and west artificial islands is carried out in an orderly manner, and the immersed tube tunnel is fully preparing for the settlement of the next pipe section.
(over)