On August 25, the launch ceremony for "Jianghan Linghang" (Jianghan Navigator), the largest-diameter open-type TBM ever made in China for the Yangtze-to-Hanjiang Water Diversion Project, was held at the assembly cavern of Civil Works Section 1 of the project, which is being constructed by Sinohydro Bureau 8. As the core equipment of the Yangtze-to-Hanjiang Water Diversion Project, the smooth launch of "Jianghan Linghang" marks that Civil Works Section 1 has officially entered the TBM tunneling stage of the water conveyance tunnel, and will play an important role in safeguarding national water security, promoting economic and social development, and serving the building of a new development pattern.

The Yangtze-to-Hanjiang Water Diversion Project is a follow-up water source project of the Middle Route of the South-to-North Water Diversion Project. It diverts water from the Three Gorges Reservoir area of the Yangtze River to the Hanjiang River, with a total water conveyance line of 194.7 kilometers, an equivalent tunnel diameter of 10.2 meters, and a designed annual water diversion volume of 3.9 billion cubic meters. As the longest pressurized water diversion tunnel currently under construction in China, once completed it will connect the Three Gorges Reservoir with the Danjiangkou Reservoir, forming a strategic water conveyance corridor from the Yangtze River to North China, substantially increasing the northward diversion volume of the Middle Route Project to 11.51 billion cubic meters, effectively alleviating the contradiction between water supply and demand in the Hanjiang River basin, and creating conditions for the long-term water diversion of the Han-to-Wei Water Diversion Project.

The "Jianghan Linghang" TBM launched this time was jointly developed by China South-to-North Water Diversion Jianghan Water Network Co., Ltd., Sinohydro Bureau 8, and China Railway Engineering Equipment Group, and is designed for extremely hard rock and high overburden geological conditions. The machine has an excavation diameter of 11.93 meters, a total length of about 180 meters, a total weight of about 3,000 tonnes, a maximum total thrust of 46,456 kN, and a total installed power of 9,200 kW. "Jianghan Linghang" integrates technologies such as intelligent TBM assisted driving, intelligent muck fragment identification, and cutterhead and cutter condition monitoring, achieving millimeter-level tunneling accuracy; it adopts a mi-shaped cutter arrangement, ultra-small cutter spacing, and full-face wear-resistant protection to cope with high-hardness rock strata such as quartz diorite and granite; and it is equipped with digital advanced drilling rigs, microseismic monitoring interfaces, and jamming warning functions to effectively address risks such as rockbursts and sudden mud and water inrushes brought by the tunnel's maximum overburden of 846 meters. Compared with the traditional drill-and-blast method, this TBM is expected to achieve an average monthly advance of more than 300 meters, improve construction efficiency by more than three times, and greatly reduce safety risks while ensuring high-precision tunnel formation.

Equipment transportation and assembly proved to be a "hard nut to crack" for the project. After "Jianghan Linghang" rolled off the production line in Deyang on December 16, 2024, it was transported to the construction site for assembly as planned after completing commissioning and acceptance. During the process, it was transported in 121 truckloads through Construction Adit No. 1 to the assembly cavern of the main tunnel at a depth of 500 meters. Faced with space constraints, the construction team innovatively adopted a "stepping while assembling" process, using a precise 270-meter step-forward to bring the cutterhead smoothly to the launch face. The construction team took the initiative to optimize the cavern layout in advance, simulate the transport route through BIM models, formulate transport contingency plans for oversized and overwidth components, scientifically allocate resources, strengthen on-site scheduling, plan the assembly sequence, and optimize process interfaces. They overcame the key difficulties of cramped assembly space and insufficient lifting capacity, eliminated the impact of various adverse conditions and external factors, and ultimately completed the equipment assembly safely and smoothly in just 62 days using only two bridge cranes, laying a solid foundation for the launch of "Jianghan Linghang" three days ahead of schedule.

As the open-type TBM with the largest diameter and the highest level of intelligence in China, the successful application of "Jianghan Linghang" will drive the upgrading of industry technical standards and provide valuable experience for the construction of subsequent national water network projects. Taking the launch of "Jianghan Linghang" as a new starting point, the construction team will advance the project construction to high standards and help make the follow-up works of the South-to-North Water Diversion Project a premium project that can stand the test of history.