17.5m diameter Herrenknecht Mixshield TBM “Shanhe” is currently being dismantled and prepared for re-assembly and deployment on a 3.3km two-storey road tunnel with three lanes in both directions in the eastern Chinese city of Jinan. A machine of this diameter has only been used twice before in the history of tunnelling – the largest being in 2015 in Hong Kong, also a Herrenknecht Mixshield, with diameter of 17.63m.
The order for the Herrenknecht subsidiary Herrenknecht Tunnelling Machinery (HTM) in China was a tough one: a machine was required to cross under the Yellow River in Jinan in eastern China, in a geological environment with high groundwater pressures and to create just a single tunnel tube for both directions of travel. A correspondingly large diameter was therefore required – 17.5m over the section of 3.3km.
To adapt to the clay, sand and silt geology and the 7.5 bar groundwater pressure under the Yellow River, Mixshield TBM technology was selected. Mixshield technology was developed by Herrenknecht and is an advancement of conventional slurry technology. The support pressure in the excavation chamber is precisely managed using an automatically controlled air cushion. This means that heterogeneous geologies and high water pressures of more than 15 bar can be controlled safely even with very large excavation diameters. An individual, new slurry circuit was designed especially for TBM “Shanhe”.
“We have also equipped the machine with our special telescopic camera in order to better monitor the tool change and the face,” says Herrenknecht project manager Zhao Bin, who has already supervised several projects for clients in China. Most recently, he supervised the two TBMs that are crossing under the Yellow River just a few kilometers from the new construction site, and the building of a road tunnel with two
tubes using two 15.71m diameter Mixshields for the Jinan Jiluo Road North Extension.
Wang Hai is Deputy General Manager of the Herrenknecht office in Beijing and isadvising the customer on the challenging project. He says: “Thanks to its efficiency, the new single-tube tunnel supports the national strategy of ecological protection and high-quality development of the Yellow River Basin. It removes a bottleneck of traffic across the river and is calculated to absorb 7.4% of the traffic volume in one
go.”
Jinan is located around 400km south of Beijing, has a population of nine million and is the capital of the Chinese province of Shandong and an important business location. The road tunnel project under the Yellow River is the second one in 2024 alone. Tunnelling is scheduled to begin in late 2024. The project aims to improve the connection between the two sides to the north and south of the Yellow River.
Herrenknecht
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