Nanchang, November 11 (Liu Fuchang, Huashan) On the morning of the 5th, at the starting shaft of the new Changjiu High-speed Railway Tianxiang Avenue Tunnel located in the High-tech Zone of Nanchang City, Jiangxi Province, with the slow rotation of the cutterhead of the "Hero" shield machine, the Tianxiang Avenue Tunnel constructed by the construction management of Changjiu Intercity Railway Company and the construction of China Railway 5th Bureau Group began to excavate. This marks the official departure of the largest diameter shield machine for high-speed railway tunnels in China.
The largest diameter shield machine for domestic high-speed railway tunnels was excavated in Nanchang, Jiangxi Province. Photo by Liu Fuchang
The new Changjiu high-speed railway is located in the north-central part of Jiangxi Province, is the key section of the Beijing-Hong Kong (Taiwan) channel in the main channel of the national "medium and long-term railway network planning" "eight vertical and eight horizontal" high-speed railway, the line leads from Lushan Station of Anjiu high-speed railway, south to Nanchang East Station of Changjiang high-speed railway, with a total length of 137.7 kilometers and a design speed of 350 kilometers per hour, which is expected to be completed and opened to traffic in 2027.
The 6.379-kilometer-long Tianxiang Avenue Tunnel is a full-line control project of the Changjiu high-speed railway, which is a single-hole double-lane tunnel, of which the shield section is 4.4 kilometers long, and the slurry balance shield machine with a diameter of 14.8 meters is used to excavate, which is the largest diameter shield machine for the domestic high-speed rail tunnel and the first large-diameter shield tunnel in Jiangxi Province. The internal structure of the tunnel adopts an integral fully prefabricated box culvert, which is the first time to be implemented in a 350 km/h high-speed rail tunnel in China.
Aerial photography of the largest diameter shield machine in a domestic high-speed rail tunnel. Photo by Liu Fuchang
Xia Xiaoren, commander of the Changjiu Headquarters of Changjiu Intercity Railway Company, told reporters that the Tianxiang Avenue Tunnel is one of the most complex high-speed rail shield tunnels in China with the most complex construction environment and geological conditions. The shield machine has to pass through 1 risk sources such as Nanchang Metro Line 78 and Yangmen Village shantytown for a long distance, and has to withstand the maximum water pressure of 6 bar (equivalent to the pressure of 60 meters of water depth), the thickness of the covering soil at the beginning of the shield section is 9.5 meters, and the thickness of the receiving (exporting) covering soil is only 9 meters, which has the characteristics of large excavation section, long tunnel interval and many geological risks.
In the face of the major difficulties in the construction of the project, the project team carried out targeted research and design in the cutterhead structure, cutter type, drive seal, pressure resistance and corrosion resistance, etc., and tailored the "Hero" shield machine, with a total length of 134 meters and a weight of about 3700,<> tons, and a number of innovative technologies such as the cutterhead hydraulic wear detection device.
The picture shows the preparation for the excavation of the largest diameter shield machine in the domestic high-speed rail tunnel. Photo by Liu Fuchang
"We will rely on the digital shield and integrate artificial intelligence algorithms to explore the autonomous tunneling mode of the shield machine for the first time, and realize the 'manned, unmanned, and automatic deviation correction' function of the shield." Wang Xing, the shield manager of the 14th Bureau of China Railway, said, "It will also give full play to the core technology advantages and rich construction experience of the large shield, and use technological innovation methods such as shield big data visualization and monitoring and early warning to ensure the safety and quality of shield construction."
After the completion and opening of the Changzhou-Kowloon high-speed railway, it is of great significance for Jiangxi Province to build an integrated comprehensive transportation system in Changzhou-Kowloon, further integrate into the Guangdong-Hong Kong-Macao Greater Bay Area, help the implementation of the development strategy of the Yangtze River Economic Belt, and promote high-quality economic and social development along the route. At that time, the Beijing-Hong Kong high-speed rail corridor will be fully connected, and Beijing will realize the whole high-speed rail travel from Hefei and Nanchang to Shenzhen (Hong Kong). (ENDS)