In August 2023, a steel giant beast with a tiger shark pattern painted on its blade was launched at the bottom of the Inner Bay in Shantou. It is called Tuodao, taking the meaning of tiger shark opening the road and overcoming difficulties. With a total length of 160 meters and a total weight of about 3300 tons, it is the first large-diameter mud water balance shield machine tailored for the submarine tunnel of the passenger and freight railway in China.

Three years have passed, and the shield machine with an excavation diameter of 13.42 meters has been gnawing forward inch by inch, now only about 470 meters away from the finish line.

Digging another 470 meters underwater

The overall construction progress of the Guang'ao Port Shugang Railway has reached 80%, and the construction of all mining tunnels has been completed. There are still more than 470 meters of shield tunnels left. The project aims to achieve the completion of the shield tunnel by June 2027 and is expected to be completed and open to traffic in the fourth quarter of 2028.

The difficulty is almost entirely on the Shantou Bay Tunnel. This control project, with a total length of about 10 kilometers, is constructed using a combination of open cut method, shield tunneling method, and mining method, with a shield tunneling section of 2990 meters. The shield tunnel section needs to cross 11 geological fault zones, located in an 8-degree earthquake zone, with a combination of soft upper and hard lower strata and full section hard rocks distributed along the line. Complex geological formations exacerbate tool wear, and during construction, it is necessary to replace the tools in the warehouse according to the actual situation, which affects the efficiency of excavation.

Next, the shield tunnel will also focus on crossing the F10 and F9 fault fracture zones. How the formation ahead changes, when to replace cutting tools, and how to reinforce the fractured zone all need to be analyzed and dynamically adjusted segment by segment. The response of the project department is to move the risk prevention and control checkpoint forward: advance geological forecasting is continuously followed up, grouting reinforcement is carried out first to reinforce the fractured strata, special construction plans are invited to experts for verification and review, tool reserves and emergency preparations are synchronized in place, forming a closed loop control of prediction, reinforcement, reserve, and emergency.

Synchronous advancement of bridges

Under the sea, the shield tunneling machine keeps moving, while above the ground, the sound of the machine rumbles. The construction of the super large bridge frame and beam across Leiguang Avenue continues to advance, and the construction of the pile foundation, bearing platform, pier body and other lower structures of the super large bridge across Shugang Avenue is being carried out simultaneously. The installation of T-beams for the entire GAGSG-1 section has begun. The tunnel and bridge advance side by side, creating conditions for the subsequent connection and full line connection of the line.

A tunnel that caters to both passenger and freight traffic

The line originates from Shantou Station of Guangmeishan Railway, passes through Shantou Inner Bay in the form of a tunnel, and connects to Guang'ao Port Area through Haojiang District. The new main line has a total length of about 16.4 kilometers and a design speed of 160 kilometers per hour. This is not an ordinary port clearance line, but a dual track railway with both passenger and freight lines - initially responsible for the collection and distribution of goods in the Guang'ao Port area and the surrounding industries, while reserving a passenger line for the Shantou Puning intercity railway to meet the future demand for intercity passenger flow in the Shantou Haojiang section.

One channel serves two purposes, avoiding redundant construction and improving the comprehensive utilization efficiency of cross sea channel resources. For the port, the significance is more direct: by 2025, the Guang'ao Port Area will achieve a container throughput of 1.7 million TEUs and operate 26 foreign trade routes. The total investment of the third phase of the project under construction is 11.4 billion yuan, and the supporting Guang'ao Station Land Formation Project will realize railway access to the port area, truly connecting the last mile of sea rail intermodal transportation.

The railway connects to the dock, allowing goods to be directly loaded into carriages from the cargo hold. This provides a foothold for rail transportation, as well as for the conversion of scattered goods to centralized goods. In addition, inland areas such as eastern Guangdong, southern Jiangxi, and western Fujian will also have a new channel to enter the sea.

It should be noted that the Shanpu intercity railway is a long-term planning project, and its subsequent construction arrangements, opening time, and specific operation plans are still subject to the information announced by the provincial party committee and government.keywords:Engineering infrastructure

At present, the remaining 470 meters are the most practical section of this railway from 80% progress to complete the entire line. The shield tunneling is advancing one meter at a time, the bridge is being erected one hole at a time, and the passage between the port and the hinterland is gradually forming on the seabed.Editor/Yang Meiling