On November 22nd, open-type rock TBM “Jianghan Neolithic” with an excavation diameter of 11.93m rolled off the assembly line of China Railway Construction Heavy Industry Corporation Limited (CRCHI). The TBM, which CRCHI says is the largest of its kind in China, will be used on the central line of the South-to-North Water Diversion Project that will divert water resources from the Yangtze River to supplement and replenish the Han River. It is also the excavation machine that will be used on the most significant and longest soft rock deformation section of the Project.
The machine is approximately 175m long and has a total weight of some 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 is capable of a real-time visualization of the geology in front of the TBM, precise autonomous control of excavation routes, automatic posture correction, and automatic excavation step changes, etc. This TBM will be applied during construction of the 3rd Section traffic tunnel and the main tunnel on the Project, with a total excavation distance of 16.35km.
The geological conditions are complex, with a large overburden present, long distances, a large tunnel diameter, multiple faults, soft rocks, high in-situ stresses, and high water-rich pressures. The TBM works will subsequently face multiple construction challenges such as high strength rock bursts, mud in-rushes, large fractures, soft rock deformations, and toxic and harmful gases.
In view of the risks and challenges on the project, the CRCHI R&D team has adapted the TBM by adopting its design to include a minimally spaced large cutterhead with a main drive anti-surge door, whilst configuring a double-speed ratio high-torque reducer with a shield lubrication and anti-friction system, with shield strain gauge detection and an early warning device. A double support system of steel arches and steel segments will be installed. The machine is equipped with a steel arch transportation and feeding system, remote-control material removal and other devices to reduce the labor intensity of construction.
Vital to improving the country’s South-to-North Water Diversion Project, diverting the Yangtze River to supplement the Han River Project is regarded as a crucial step in creating the main framework and artery of the national water network.
After the implementation, 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, forming a new water supplying network and providing a more abundant and secure water resource for these regions.
Comments: