【Domestic News】115 Meters Under the Sea! The Deepest Undersea Tunnel TBM in China

On August 25, the Shenjiang Tunnel TBM, for the construction of the deepest undersea tunnel in China, successfully rolled off the production line, promoting the construction of the Pearl River Estuary Tunnel Project.

The Shenjiang Tunnel is 13.69km long and designed speed is 250km/h, of which 9,175m is constructed by CRTG. The maximum undersea depth of Shenjiang Tunnel is 115m, which is the deepest record of undersea tunnels in China. The maximum water pressure is 1.06MPa (The strength exceeds 10 standard atmospheric pressure), which is the highest in the world.

The Shenjiang Tunnel TBM diameter is 13.32m, the total length is 133m, and the total weight is about 3900t. Considering the characteristics of engineering geology, the research team is equipped with innovative technologies such as atmospheric pressure composite cutter head with small cutter spacing, scalable main driver, automatic compensation of ultra-high pressure , four-circuit holding pressure, and air cushion direct excavation system, which provide a strong guarantee for safe and efficient tunnel construction.

There is no similar engineering experience, TBM equipment and design standard for the ultra-high water pressure of Shenjiang Tunnel in China. The TBM had to replace the worn tools under ultra-high water pressure in the unfavorable stratum with extremely risky and difficult. In addition, the TBM had to achieve precise docking after long-distance undersea advancing, which requires extremely stringent dynamic control of construction.

The Shenjiang Tunnel will provide unique example and valuable experience for the world's undersea tunnel engineering technology.