Chinese Deepest Undersea Tunnel Boring Machine “Shenjiang Yihao” Rolled off the Production Line in CRCHI
On August 23, 2021, in the Changsha First Industrial Park of China Railway Construction Heavy Industry Corporation Limited (hereinafter referred as CRCHI), a large-diameter shield machine with a cutterhead decorated with the face of a lion rolled off the production line. This shield machine has an excavation diameter of 13.42 meters, a total length of 130 meters, and a total weight of 3,800 tons. It will participate in the construction of China's deepest submarine tunnel-the Pearl River Estuary Tunnel of the Shenzhen-Jiangmen Railway.
The Pearl River Estuary Tunnel is a key control project of the Shenzhen-Jiangmen Railway. "Shenjiang Yihao" will cross the section with a total length of 3590 meters. The whole line excavates long-distance downhill and passes through the Pearl River estuary. The engineering geological conditions are extremely complex, including soft soil, hard rock, soft and hard uneven, bedrock bulge, crossing multiple fractured zones. With the maximum buried depth of 106 meters and high water pressure construction area of 110 meters, the tunnel is currently the domestic underwater shield tunnel with the longest buried depth and the highest water pressure.
Specific to the construction difficulties in sea areas such as ultra-high water pressure, super-hard rock formations, long-distance downhill excavation, continuous crossing fractured zones, and strong seawater corrosion, the development team has carried out a targeted selection design and a configuration of the normal and under pressure heavy composite cutterhead, a retractable main drive, a double-layer shell. The machine integrates a series of intelligent systems such as high-precision large-flow circulation, high-efficiency heavy-load material transportation, main drive seal automatic pressurization, simultaneous single and double liquid grouting, shield tail gap measurement, automatic segment selection and floating detection, tunnel ventilation and refrigeration, which improve the adaptability of the shield machine and provide a guarantee for the safe and efficient construction of the project.
"Shenjiang Yihao" successfully rolled off the assembly line, marking that the Pearl River Estuary Tunnel of the Shenzhen-Jiangmen Railway is about to enter the shield construction stage. The shield machine will be disassembled and transported to the construction site, and the whole system will be assembled and debugged to ensure that the excavation starts as soon as possible.