China's tunnel boring machine, the "Shenjiang No. 1," has set a world record for constructing the deepest underwater high-speed rail tunnel at 113 meters. The tunnel is located at the Pearl River estuary in southern China and is a key project of the 116-kilometer-long Shenzhen-Jiangmen Railway. Once completed, it will further improve the rail transit network in the Guangdong-Hong Kong-Macao Greater Bay Area.

A massive cutterhead acts as the "head" of the "Shenjiang No. 1." Rotating continuously, the cutterhead breaks through rock and soil. Behind the cutterhead is the assembly section. As the machine advances, workers install tunnel lining segments, each about 2 meters wide. They excavate and line the tunnel simultaneously to improve efficiency.

The "Shenjiang No. 1" recently advanced by more than 4 kilometers, reaching a depth of 113 meters. However, the deepest point of the tunnel lies 116 meters underwater, where water pressure is immense.