The "Jinggangshan" shield machine is launched.
Yesterday, as the cutterhead of the "Jinggangshan" shield machine slowly rotated, the shield machine for the tunnel project of the Phase II Water Diversion and Emergency Water Diversion Project in the upper reaches of the Yongjiang River in Nanning City was successfully launched. This is also the first time that shield tunneling technology has been applied in a municipal water diversion tunnel project in Guangxi.
As one of the major projects coordinated and promoted at the Guangxi Zhuang Autonomous Region level, the Phase II project in the upper reaches of the Yongjiang River will draw water separately from the upper reaches of the Yongjiang River (the Zuojiang River and the Youjiang River), build three pumping stations—the Zuojiang Pumping Station, the Youjiang Pumping Station, and the Shibu Pumping Station—and renovate the Laokou Pumping Station. At the same time, a water supply pipeline with a total length of 28.2 kilometers will be built, with a total water diversion capacity of 2.68 million cubic meters per day.
The construction tasks undertaken by China Railway No. 4 Engineering Group include 9 working shafts, 3 shield tunnel sections totaling 12.6 kilometers, and 1 drill-and-blast tunnel section totaling 4.9 kilometers. The project adopts a domestically leading construction technique for large-diameter, long-distance water conveyance tunnels. The tunnel not only needs to pass through complex geological structures, but also faces multiple challenges such as passing beneath the Youjiang River, karst caves, and existing expressway lines and other structures, as well as shield construction.
According to the technical director of the Yongjiang water diversion project of China Railway No. 4 Engineering Group, the "Jinggangshan" shield machine launched this time has a total length of 155 meters, an excavation diameter of 5.68 meters, and can achieve a horizontal turning radius of 250 meters. This model of shield machine is not the common earth pressure balance shield machine, but rather an earth pressure/slurry dual-mode shield machine suitable for river-crossing tunnels and capable of overcoming special environments such as high groundwater content and water bodies above. When the shield machine advances, the excavated muck can be pumped to the surface through the slurry circulation system for separation. The separated muck is directly transported away, while the slurry can be recycled and reused. After all shield machines complete their launch operations, 3 shield machines will advance simultaneously, with a cumulative daily advance of 25 meters.
It is reported that after the Phase II Water Diversion and Emergency Water Diversion Project in the upper reaches of the Yongjiang River is completed, Nanning City will take the lead in China in building a dual-water-source system of the same scale operating jointly, forming a raw water intake pattern of "two rivers developing in parallel and serving as backups for each other." In emergency situations, unilateral water diversion can be achieved, enabling flexible response to emergency support needs arising from various water source failures, fully ensuring the safe operation of the urban raw water system, and adding "double insurance" to Nanning City's water supply safety.
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