On March 31st, with the completion of the 953 ring advance of the "Haitian" shield machine, the main tunnel excavation of the southern line of the Jiaozhou Bay Second Tunnel, constructed by China Railway 14th Bureau, exceeded 2000 meters, marking significant progress in this world-class project.

The second tunnel of Jiaozhou Bay is 17.48 kilometers long, consisting of two main tunnels and one service tunnel. It is currently the longest and most difficult to implement underwater road tunnel in the world. The project team faced complex geological conditions and innovatively adopted atmospheric pressure replaceable rolling cutters, a new slag removal system, and shield stable seismic technology to achieve efficient construction of over 140 meters per month in hard rock formations. In addition, the synchronous assembly technology of box culverts has been applied for the first time in service tunnels, solving the problems in the same level of shield tunneling machine rail transportation industry and greatly improving construction efficiency.

After the completion of the tunnel, Qingdao will enter the "dual tunnel era", forming a cross sea transportation network together with the Jiaozhou Bay Tunnel, the Cross Sea Bridge, and the Ring Expressway, significantly alleviating regional traffic pressure, promoting the integrated development of "green and yellow cities", and providing important support for Qingdao's construction as a global ocean center city. China Railway 14th Bureau will continue to lead with technological innovation, promote this major project with high standards, and assist in the high-quality development of cities. (This article is from the official website of Jian Dao www.seetao.com. Reproduction without permission is prohibited, otherwise it will be prosecuted. Please indicate Jian Dao website+original link when reprinting.) Jian Dao website strategy column editor/Wu Juan