An open-type rock TBM for China’s South-to-North Water Diversion Project has rolled off the production line at Railway Construction Heavy Industry Corporation Ltd (CRCHI).
The company says the 11.93m-diameter machine is the largest of its kind in China.
TBM Jianghan Neolithic will be used on the central section of the South-to-North Water Diversion Project that will divert the Yangtze River to supplement the Han River. It will also excavate the largest and longest soft rock deformation section of the project.
The TBM is approximately 175m long and weighs around 3,000 tons. It has a designed minimum radius of 800m and adapts to a maximum slope of 10%. With an immersive intelligent excavation system, it has real-time visualisation of the geology in front of the TBM, precise autonomous control of excavation routes, automatic posture correction, and automatic excavation step change. TBM Jianghan Neolithic will be deployed on the construction of the 3rd Section traffic tunnel and main tunnel, excavating a total distance of 16.35km.
The project is considered to be one of China’s water diversion undertakings.
The geological conditions are complex, with a large overburden, long distance, large tunnel diameter, multiple faults, soft rocks, high in situ stress, and high water pressure. As a result, the TBM will face many construction challenges such as high-strength rock bursts, mud inrushes, large fractures, soft rock deformation, and harmful gases.
In response to these conditions, the CRCHI R&D team designed the TBM with a small spaced, large cutterhead, double support of steel arch and steel segments, main drive anti-surge door, and configured a double-speed ratio high-torque reducer, shield lubrication and anti-friction system, with shield strain gauge detection and early warning device.
The TBM also features a steel arch transport and feed system, and remote-control material removal.
Diverting the Yangtze River to supplement the Han River Project is a crucial step in creating the main framework and artery of the national water network. Once this is done, the South-to-North Water Diversion Project and the Three Gorges Dam Project will be connected, linking the Yangtze River Basin, the Han River Basin, and the Beijing-Tianjin-North China region to form a new water supply network and improve water resources for these regions.
