Recently, the first curved pipe section E15 of the Dalian Bay Undersea Tunnel, the first large immersed tunnel built by First Harbor Engineering under CCCC in the northernpart of China. So far, the total installation length has reached 2,591 meters.

The immersed shaft of the E15 pipe section has a length of 148 meters, a width of 33.4 meters, a height of 9.7 meters, a weight of about 47,000 tons, as well as a 0.65% inclination, which is the biggest one among all the curved pipe sections.

The foundation bed levelling of the curved pipe section is different from that of a straight one because the gravel ridges are arranged in a parallel offset way instead of justin a parallel way, thusrequiring technical personnel to do the levelling under stricter conditions. Before levelling the pipe section, the project team continued optimizing levelling techniques and adopted a levelling ship navigation and levelling system, effectively guaranteeing the levelling precision and laying a solid foundation for the installation of the E15 pipe section.

After the installation of the E15 pipe section, the Dalian Bay Subsea Tunnel and Guangming Road Extension projectwill speed up the construction. The project team will strive to promote the installation of the remaining3 pipe sections and the last batch of joints so as to complete the project at an early date.

In early May, the other 3 pipe sections including E16, E17, E18 successfully undocked.Besides, the demolition project of the basin cofferdam on the south bank of the Dalian Bay Undersea Tunnel was successfully finished recently and 15 days ahead of schedule, creating the necessary conditions for the installation of the last pipe section E18.