On August 23, at CRCC Heavy Industry's Changsha First Industrial Park, a large-diameter tunnel boring machine with a majestic lion pattern painted on its cutterhead rolled off the line in glory. With an excavation diameter of 13.42 meters, a total length of 130 meters and a total weight of 3,800 tons, this TBM will take part in the construction of the Pearl River Estuary Tunnel on the Shenzhen-Jiangmen Railway, China's deepest subsea tunnel.

Named "Shenjiang No. 1," the machine was jointly built by CRCC Heavy Industry and China Railway 14th Bureau Group. Its cutterhead features a painted "awakening lion" motif, and the imposing three-dimensional design with rich layering highlights the distinctive regional culture of Guangdong.

The Pearl River Estuary Tunnel is a key controlling project of the Shenzhen-Jiangmen Railway. "Shenjiang No. 1" will bore a 3,590-meter section, driving along a long downhill alignment beneath the Pearl River estuary. The engineering geological conditions are extremely complex, combining soft soil, hard rock, mixed soft-hard ground and bedrock protrusions, and crossing multiple fault fracture zones. With a maximum burial depth of 106 meters and a high-water-pressure construction section of 110 meters, it is currently China's underwater shield tunnel with the greatest burial depth and the highest water pressure.

In response to the difficulties of subsea tunnel construction—ultra-high water pressure, extremely hard rock strata, long-distance downhill boring, continuous crossing of fault fracture zones and highly corrosive seawater—the development team carried out targeted selection and design of the TBM. It is equipped with a heavy-duty combined cutterhead for atmospheric and pressurized operation, a retractable main drive and a double-layer shell, and integrates a series of intelligent systems including high-precision, large-flow slurry circulation, efficient heavy-load material transport, automatic pressurization of the main drive seal, synchronous single- and dual-fluid grouting, shield tail clearance measurement, automatic segment selection and floating detection, and tunnel ventilation and cooling. These enhance the machine's adaptability and safeguard safe, efficient construction.

The successful rollout of "Shenjiang No. 1" marks that the Pearl River Estuary Tunnel of the Shenzhen-Jiangmen Railway is about to enter the shield tunneling stage. Next, the TBM will be dismantled and transported to the construction site for full-system assembly and commissioning, ensuring early launch and boring so that China's high-speed rail can speed beneath the seabed at a depth of 100 meters, providing a unique sample and valuable experience for subsea tunnel engineering worldwide.

The Shenzhen-Jiangmen Railway has a main line length of 116.12 kilometers and a design speed of 250 km/h. Located at the center of the Guangdong-Hong Kong-Macao Greater Bay Area, it is an important part of the coastal corridor of the national "eight vertical and eight horizontal" high-speed railway network and a major transport infrastructure project supporting the development of the Greater Bay Area and the Guangdong Pilot Free Trade Zone.

The Shenzhen-Jiangmen Railway has a planned construction period of 66 months and is expected to be completed and opened to traffic in 2025. Once open, it will help create a half-hour living and economic circle in the Greater Bay Area, directly drive coordinated regional development between eastern and western Guangdong and the Pearl River Delta, and enable half-hour high-speed rail connectivity between Shenzhen's Qianhai Free Trade Zone and Guangzhou's Nansha Free Trade Zone.