China's largest-diameter dual-shield TBM launched to boost major water diversion project

China's largest-diameter dual-shield, self-developed TBM (Tunnel Boring Machine), the "Jianghan Ping'an," was launched on Sunday in Yichang, Central China's Hubei Province, as part of a project to channel water from the Three Gorges Reservoir area to the Hanjiang River.

This state-of-the-art equipment was specifically introduced to ensure high-quality construction of the project's civil works, Chinanews.com reported, noting that its deployment is expected to facilitate the efficiency and optimization of China's water resource allocation projects.

Jointly developed by several domestic companies including China Railway Construction Heavy Industry Co and China Railway No. 3 Engineering Group, the "Jianghan Ping'an" TBM stands out as the largest and most advanced dual-shield TBM in China's current tunnel construction projects, according to media reports.

The TBM features an excavation diameter of 11.93 meters, a total length of about 180 meters and a weight of about 3,550 tons.

Its operation will help overcome critical challenges, including large-diameter, long-distance excavation in ultra-hard rock, high in-situ stress causing rockbursts, and excessive levels of hazardous gases.

The TBM is equipped with cutting-edge technologies such as induced polarization geophysical detection, machine jamming pre-warning systems, cutter status monitoring systems, and an innovative standard advanced drilling system. These features enable it to tackle complex geological conditions, including deep burial with high rock stress, ultra-hard rock, rockbursts and high external water pressure.

More than 3.8 kilometers of the main tunnel and more than 16 kilometers of branch tunnels have been excavated. Of the 10 TBMs deployed for the project, six have been successfully assembled, and three have commenced tunneling, with the overall progress of TBM operations having exceeded expectations.

The project that channels water from the Three Gorges Reservoir area to the Hanjiang River is the first major initiative of the follow-up work for China's South-to-North Water Diversion Project. It is a landmark project for building a robust national water network and plays a critical role in optimizing China's water resource allocation and ensuring national water security, according to media reports.