On July 11, excavation began on the Tangshan Road Tunnel, part of the project to add the Tangshan Road interchange and connecting line to the Qingdao-Yinchuan Expressway. The tunnel's maximum cross-section excavation clear span reaches 32 meters, making it the largest-span transportation tunnel in Asia.

It is reported that the mined section of the Tangshan Road Tunnel has a total length of 1.15 km, with a main line designed as twin tubes with 8 lanes, combining an ultra-large cross-section with an ultra-small clear distance. The maximum cross-section excavation clear span reaches 32 meters, with a height of 19 meters, equivalent to the height of a 6- or 7-story building, making it currently the largest-span transportation tunnel in Asia. The tunnel also has the most frequently varying cross-sections in this project, with as many as 18 types of excavation cross-sections and as many as 8 types of structural cross-section lining; the largest excavation cross-section reaches 480 square meters, larger than a standard basketball court. The minimum spacing between the excavation cross-sections of the mainline lane tunnel and the future lane tunnel is 0.3 meters, and the central rock pillar is difficult to preserve, carrying a high risk level.

Aerial view of the west portal

Schematic diagram of the tunnel

As one of the key projects in Qingdao's three-year action plan for urban renewal and urban construction, this project is an important axis for integrated regional development featuring "east-west connectivity and multi-cluster radiation." Once completed, it will be of great significance to the sustained and healthy development of Qingdao's national economy, the urban renewal and upgrading of Licang District, and the building of the urban framework of a greater Qingdao.