On February 24, the reporter learned from China Railway Construction Corporation Limited, the builder of the Gongbei Tunnel, that the Gongbei Tunnel—the core control project of the Zhuhai Link Road of the Hong Kong-Zhuhai-Macao Bridge and the world's largest cross-section highway tunnel—has been fully completed.
According to reports, the Gongbei Tunnel has a total length of 2,741 meters and consists of an undersea tunnel and an urban underground tunnel, arranged in a pattern of "first separated and parallel, then vertically overlapping, and finally separated and parallel again." The mined section of the tunnel passing beneath the Gongbei Port is 255 meters long, with an excavation cross-section of 336.8 square meters, equivalent to the size of a basketball court; the maximum cross-section is over 20 meters high, equivalent to the height of a seven- or eight-story building, making it the world's largest cross-section tunnel.
The stratum in the mined section of the tunnel is soft and rich in groundwater, less than 5 meters from the ground surface, and the nearest distance to the "densely distributed" pile foundations of the port is only 46 centimeters. The slightest mistake could have a significant negative impact on port clearance, making it one of the most challenging highway construction projects in the industry. The construction of the Gongbei Tunnel could not affect the daily average of 300,000 passengers passing through Gongbei Port, and "must not touch the densely distributed building pile foundations beneath the Zhuhai and Macao ports, nor allow groundwater connected to seawater to intrude."
The completion of the Gongbei Tunnel marks a major breakthrough in the key core technologies of the Zhuhai Link Road of the Hong Kong-Zhuhai-Macao Bridge. Among them, the complete set of construction technology for curved pipe-roof jacking and the long-distance large-cross-section horizontal circumferential one-time freezing technology have both filled gaps in China's construction field.
It is understood that the Gongbei Tunnel is located in the bustling urban area of Zhuhai, close to Macao, with beautiful natural scenery along the route, and is situated in a water and noise environment-sensitive area. The requirements for landscape design and construction process control are higher than those of traditional highway projects. As the only "landing point" of the Hong Kong-Zhuhai-Macao Bridge on the mainland, the Zhuhai Link Road will provide convenience for residents of Guangdong, Hong Kong, and Macao to communicate. At the same time, it will open up a passage from the west bank of the Pearl River to Hong Kong and Macao, helping to promote the interconnection of transportation construction in the Guangdong-Hong Kong-Macao Greater Bay Area.