Xiamen Electric Power and Qingshui Island Tunnel project will be excavated from the coast to the end of the island and is expected to be completed and put into use in 2026

Recently, it was learned that Xiamen's key livelihood project - Xiamen Power and water Island Tunnel project has entered the shield phase of the sea section, the project coastal bottom to the end of the island, is expected to be completed and put into use in October 2026.

It is reported that the project is the third channel of power into the island overhead cable and water into the island common corridor civil engineering, line from the Song Yu power plant in Haicang, across the west sea, and finally the island 220kV Xia He substation, the total length of the line is 6177 meters, of which, the sea section tunnel length of 3078 meters, tunnel diameter of 6.7 meters, belongs to the project line of control engineering.

At the construction site of the Haicang end of the project, about 28 meters underground, 7.02 meters in diameter of the special type shield machine issued a blast, under the rotation of the shield cutter, the seabed geological layer composed of rocks and mud, like "onion" is peeled off layer by layer, after transmission, these construction waste will be sorted on the ground, recycling.

In order to meet the complex working conditions of the first line of the project, we have linked with a number of units to carry out targeted design of the shield machine. The cutterhead structure adopts the form of "6 main beam +6 auxiliary beam", and the 19-inch hob with the conventional shield blade is longer and thicker to improve the durability of the equipment and greatly enhance the rock breaking ability. At the same time, the hob installation method and anti-loosening measures are optimized to reduce the bolt tightening time and the risk of falling the tool caused by hard rock formation drilling jitter. At present, the sea crossing section of the project has been completed about 659 meters, and the section from Songyu Power Plant to Jiangang has also been completed. In the late construction of the full-section hard rock stratum, the project will continue to do the inspection and replacement of the atmospheric pressure opening tool to ensure that the construction safety is implemented.

As the master plan of Xiamen City and the 22nd batch of municipal key infrastructure projects, the completion and operation of Xiamen Power and water Tunnel project is expected to improve the reliability of power supply in Xiamen Island, while changing the current status of single water source on the island, and improve the urban supporting facilities, integrate urban land resources, improve the west sea landscape. It is of great significance to promote Xiamen to build a node city in the new development pattern.

The most critical link in the undersea shield

The person in charge of the project agent construction unit introduced that the project started the shield in June 2023, and from the progress point of view, the shield machine can advance about 6 meters per day on average. Today, the shield machine has entered the hard rock strata of the full cross-section of Lantau Island, which is the most critical link in the submarine shield project.

It is understood that there are four bedrock bumps along the cross-sea section of Xiamen Electric Power and Qingshui Island Tunnel project, and Lantau Island belongs to the "largest" one, with a hard rock formation length of about 600 meters and an average rock strength of 167 mpa, which is equivalent to 1.67 tons of pressure applied on an area of 1 square centimeter to break the rock. To crack this "hard bone" is a great test for construction technology and professional level.