Recently, the Shantou Bay Subsea Tunnel of the Shantou Railway has officially entered the substantive construction stage. The project is the world's first single-hole double-track high-speed rail submarine tunnel with a design speed of 350 kilometers per hour.

Tunnel entrance blasting site

Shanshan Railway

The Shantou (Tou)-Shantou (Wei) Railway will be connected with the Guangzhou-Shantou Railway under construction, closely linking Guangzhou with cities such as Huizhou, Shanwei, Shantou, and at the same time connecting Xiamen-Shenzhen, Ganshen and Guangshen railways. According to the plan, the Shantou Railway will also connect the Shantou-Zhangzhou Railway to the east, and together with the Hangzhou-Wenzhou Railway, Hangzhou-Taiwan Railway, Wen-Fu and Fu-Xia Passenger Railway, it will form a new high-speed railway passenger transport channel along the southeast coast.

The Shantou Bay Subsea Tunnel is located in Shantou City, Guangdong Province. It passes through Shantou Bay between Mayu Island and Dezhou Island on the lower reaches of the Shantou Bay Bridge. The tunnel is 9781 meters in length and is a full-line control project of the Shantou Railway. The design speed is 350 kilometers per hour, and the combined construction scheme of shield method + mining method is adopted. The tunnel is located in a seismic intensity zone of 8 degrees, passing through geological fracture zones, densely packed rocks and multiple faults. The tunnel body in the mine section alone has to pass through 13 fault fracture zones. The surrounding rock is extremely loose, and it is prone to emergence during excavation. The flooding and mud, the safety risk is extremely high, the construction is extremely difficult. In the competition with complex geology, the project department organized several expert group on-site consultations, rationally selected excavation methods based on changes in surrounding rock, optimized support parameters, strengthened realistic analysis of procedures, and improved work efficiency while ensuring safety and quality.

Plan of Shantou Bay Subsea Tunnel

High-intensity earthquake zone crosses dense fault fracture zone

High water pressure environment in sea area

Most of the tunnels are located in high water pressure risk areas. The maximum water pressure can reach 0.97 MPa. Under such strong pressure, water can form a water column as high as 97 meters, which is the largest underwater tunnel in China.

High grade corrosive environment in sea area

The Shantou Bay Subsea Tunnel has been exposed to high-pressure seawater for a long time. The tunnel structure needs to adapt to the strong corrosive environment while withstanding high water pressure penetration. The combined effect of the two makes the subsea tunnel environment more severe.

Complex engineering geological conditions

Schematic diagram of engineering geology of Shantou Bay Subsea Tunnel

Diverse construction methods

Schematic diagram of construction method of Shantou Bay Subsea Tunnel

After the project is completed and opened to traffic, it will accelerate the urbanization development process of the areas along the route, help form a new high-speed rail economic belt, further promote the economic revitalization of eastern Guangdong, shorten the development distance between eastern Guangdong and the Pearl River Delta, and promote the coordinated economic and social development of Guangdong Province. Editor/He Yuting