On March 18, 2022, the Zhanjiang Bay Submarine Tunnel of the Guangzhan High-speed Railway constructed by the China Railway 14th Bureau Group has been excavated to 1,400 meters, and successfully passed through the East Sea Wall and entered the waters of Zhanjiang Bay, marking the start of the only shield tunnel on the entire line.

The Zhanjiang Bay Undersea Tunnel is a controlled project of the entire Guangzhan high-speed railway line. It has a single hole and two lines. The shield section is 7.3 kilometers long and the excavation diameter is 14.33 meters.

The underpass covers nearly 2.5 kilometers of Zhanjiang Bay waters, crosses the main waterway of Zhanjiang Bay, runs parallel to the Zhanjiang Bay Bridge, and crosses the pier pile foundation of the bridge ramp, and the closest distance to the bridge pile is only 1.2 meters. The bottom of the shield is subjected to high water pressure, which is equivalent to a force of 5.4 kg on an area the size of a fingernail. At the same time, shield tunneling requires long-distance traversing of the fully broken floury clay stratum. The cutter head is very easy to form mud cakes. The amount of waste mud during construction is large, and the mud treatment is difficult.

Excavation construction site

In order to reduce the risk of subsea tool changing construction, under the premise of fully implementing the epidemic prevention and control measures, the project department carried out the maintenance and optimization of the shield machine before entering the sea area, and replaced the durable tools. Experts in the industry were invited to conduct demonstration and conditional acceptance of the special construction plan for the sea area section, and organized and carried out emergency drills for shield tunnel construction with water and sand gushing, which improved the emergency rescue capabilities of all staff and provided protection for the shield tunnel to safely pass through the sea area.

During the sea penetration, the project department will make full use of the intelligent command system to monitor the tunneling attitude of the shield machine in real time, strictly control the tunneling parameters, and grasp the relevant data in real time, so as to escort the crossing of Zhanjiang Bay.

Inside the forming tunnel

The main line of the Guangzhan high-speed railway is about 401 kilometers long, and the construction of the whole line will start on June 30, 2020. The line starts from Guangzhou Railway Station, ends at Zhanjiang North Railway Station, and connects to Zhanjiang Hub in the west, with a designed driving speed of 350 kilometers per hour. After completion, it will realize a 90-minute mutual connection between the central city of Guangzhou and the central city of Zhanjiang, and become an important part of the high-speed railway channel connecting the Guangdong-Hong Kong-Macao Greater Bay Area, Hainan Free Trade Port, and Beibu Gulf urban agglomeration, and enhance the regional economic status of western Guangdong , and promote the overall economic and social development along the route.Editor/Ma Xue