On June 23, at a depth of 102 meters beneath the seabed in the Pearl River Estuary Tunnel of the newly built Shenzhen–Jiangmen Railway (hereinafter referred to as the Shenzhen–Jiangmen Railway), the "Shenzhen–Jiangmen No. 1" shield tunneling machine of China Railway 14th Bureau Group advanced safely to ring 1720, successfully crossing 17 fault zones. This marks that China's deepest underwater tunnel construction has conquered the 490-meter fault zone section and is about to reach its lowest point at 106 meters below the seabed.

The 13.69-kilometer Pearl River Estuary Tunnel is a key controlling project of the Shenzhen–Jiangmen Railway, with a maximum burial depth of 106 meters. Its maximum water pressure is equivalent to bearing 10.6 kilograms of pressure on an area the size of a fingernail. It is China's underwater tunnel with the greatest burial depth and highest water pressure, and also the world's deepest subsea high-speed railway tunnel.

The shield tunneling machine has successively crossed 13 types of strata, 5 types of composite geology, and 17 fault zones, among which the fault zone and its branch sections total 490 meters in length. The widest, No. 15 fault zone, is 32.5 meters wide, and the granite strength reaches up to 124.6 megapascals, with uneven rock strata, uneven hardness, great burial depth, and high water pressure. During construction, risks such as tunnel face collapse, accumulation and sluggish discharge in the shield machine's front chamber, abnormal collision and damage of cutters, jamming of the cutterhead, and failure of the tail seal are highly prone to occur, necessitating continuous construction.

According to reports, the project team of the SJSG-1 section of the Shenzhen–Jiangmen Railway strengthened the research and application of intelligent construction technologies and adopted advanced geological prediction technology to accurately detect and provide early warning of the geology within 100 meters ahead. They developed and used new shield cutters and wear-resistant materials, installed a cutter wear monitoring system to monitor changes in parameters such as cutter temperature and rotational speed in real time, with autonomous pop-up alarms. Through the collection, analysis, and assessment of key indicators, they accurately determine cutter wear conditions, achieving intelligent analysis, precise measures, and efficient tunneling. Since entering the fault zone section in November last year, tunnel tunneling has continued for 7 months, with an average daily advance of 5 meters.

The "Shenzhen–Jiangmen No. 1" shield tunneling machine is responsible for tunneling 3,590 meters from Dongguan toward Guangzhou's Nansha direction. After breaking through the fault zone section, it enters a relatively intact hard rock section and continues tunneling toward 106 meters below the seabed.

The Shenzhen–Jiangmen Railway is an important component of the coastal corridor of China's "Eight Vertical and Eight Horizontal" high-speed railway main corridors. Once completed and opened to traffic, it will directly radiate and drive the coordinated regional development of eastern Guangdong, western Guangdong, and the Pearl River Delta, enabling half-hour high-speed rail interconnection between Shenzhen's Qianhai Free Trade Zone and Guangzhou's Nansha Free Trade Zone.