The first shield tunnel across the sea in China has been completed

On the morning of March 10, the much-concerned construction of xiamen metro line 2 ushered in another key node -- the control section of the entire line of nodal project "haicang avenue station - dongdu station" cross-sea tunnel section was fully completed, marking that the entire line of rail paving into the undersea tunnel operations. The tunnel, designed by the fourth academy of China railway construction and constructed by the 14th bureau of China railway construction, is the first and most technically difficult shield tunnel to cross the seabed in China.

The sea crossing section of xiamen metro line 2 is 2,736 meters long, of which the shield section is about 2,500 meters. Different from the previous underwater tunnels of rivers, lakes and other rivers with relatively uniform strata, the cross-sea tunnel passes through the complex and changeable geological conditions of the strata, integrating the silt soft soil layer, the breeze fossil English sandstone layer, the upper soft and lower hard strata, and accompanied by solitary rocks, which is called "geological museum". In addition, the project basically covers all construction methods and envelope forms in subway construction.

In December 2014, the construction of the starting well of the cross-sea tunnel began, which was the first starting point of line 2. After 5 years of construction, it was successfully completed and became the last section of the whole line to be transferred to the track-laying area, indicating the difficulty.

TieSiYuan tunnel design, zao Ming should be introduced, head of shield tunnel crossing the boulder group and in the process of the fracture zone, innovation to use in the slurry shield HengDun mud pressure maintaining maritime grouting reinforcement technology, solve the broken stratigraphic constraints not holding a big technical problem, not only ensure the safety of the tunnel, the economic and reasonable, more make the concept of "science and technology of tunnel" to carry out, improve the technological content of the project.

On March 10, 2019, the shield tunnel of xiamen metro line 2 was completed

Xiamen metro line 2 is the east-west skeleton line of the xiamen rail transit network, which constructs the fast cross-sea connection between xiamen island and haicang district, and takes into account the island and off-island resource sharing public transport backbone function. It is expected to start trial operation at the end of 2019.