An undersea tunnel at a depth of 68 meters beneath the Shantou Bay in eastern Guangdong province was successfully connected on Mar 26 after a tunnel boring machine broke through rock with a diameter of 14.57 meters, nearly as high as a five-story building.

The connection marked significant progress in the construction of the undersea tunnel, setting multiple records in both domestic and international undersea tunnel construction.

The tunnel is the world's first high-speed rail tunnel featuring a single bore with two tracks. With a designed speed of 350 kilometers per hour, it forms a crucial connection in the high-speed railway between Shantou and Shanwei in eastern Guangdong.

Source：chinadaily.com.cn
Editor：Di Wu