The Shantou Su'Ai undersea tunnel is being built to connect the northern and southern parts of the city of Shantou in China. These are two tunnels (or you can say two tubes) -which go under the South China Sea.

Chinese contractor China Railway Tunnel Group Co., Ltd. decided on the best equipment there exists for such difficult tunnelling: Herrenknecht Tunnel Boring Machine with a diameter of 14.96 metres.

Each of the tunnels is 6.68 km long. More than 3 kilometers of each tunnel is bored via Herrenknecht TBM. The Mixshield TBM is equipped with a cutter head accessible under atmospheric pressure for rapid tool change.

In May, the boring of the eastern tunnel tube is completed.