On November 22, the open-type rock TBM with an excavation diameter of 11.93 meters, the largest of its kind in China, rolled off the assembly line of China Railway Construction Heavy Industry Corporation Limited (CRCHI). The TBM will be used in the middle line of the South-to-North Water Diversion Project to divert the Yangtze River to supplement the Han River. It is also the excavation machine for the largest section and the longest soft rock deformation section of the Project which diverts the Yangtze River to supplement the Han River.
The TBM is named "Jianghan Neolithic" and is manufactured by CRCHI. The machine is approximately 175 meters long and has a total weight of approximately 3,000 tons. It has a designed minimum radius of 800 meters and adapts to a maximum slope of 10%. With the immersive intelligent excavation system, it has the functions of real-time visualization of the geology in front of the TBM, precise autonomous control of excavation routes, automatic posture correction, automatic excavation step change, etc. This TBM will be applied in construction of the 3rd Section traffic tunnel and main tunnel of the Project, with a total excavation distance of 16.35 kilometres.
The geological conditions of Diverting the Yangtze River to supplement the Han River Project are complex, with the characteristics of large overburden, long distance, large tunnel diameter, many faults, many soft rocks, high in-situ stress, high water-rich pressure, etc. Consequently the TBM construction is faced with multiple construction challenges such as strong rock bursts, mud inrush, large fractures, soft rock deformation, toxic and harmful gases, etc. Therefore, this project is considered as the longest single hole, the largest tunnel diameter, and the highest comprehensive difficulty in China's long-distance water diversion project under pressure.
In view of the construction risks and difficulties of the project, the CRCHI R&D team has improved the adaptability of the TBM to poor geology by adopting the design of small spacing, large-scale excavation cutter head, double support of steel arch and steel segments, and main drive anti-surge door, and configuring the double-speed ratio high-torque reducer, shield lubrication and anti-friction system, and shield strain gauge detection and early warning device. The machine is equipped with steel arch transportation and feeding system, remote-control material removal and other devices to reduce the labour intensity of construction and provide strong support for project construction.
As a vital part of further improving the South-to-North Water Diversion Project, Diverting the Yangtze River to supplement the Han River Project is a crucial step in forging the main framework and artery of the national water network. After the implementation, 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, eventually forming a new water supplying network and providing better water resources for these regions. For further information please visit https://en.crchi.com/ .
