Herrenknecht delivers 17.5m diameter TBM for China infrastructure project
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Herrenknecht delivers 17.5m diameter TBM for China infrastructure project

A Mixshield tunnel boring machine (TBM) has been delivered by Herrenknecht for the construction of a 3.3km two-storey road tunnel with three lanes in each direction. The project is taking shape in Jinan, China.

The order for the Herrenknecht Tunnelling Machinery (HTM) was for a machine to cross under the Yellow River in Jinan, in a geological environment with high groundwater pressure, and to create just one tunnel tube for both directions of travel. Given the requirements, a large diameter was required: 17.5m. The TBM’s 5,600kW cutterhead drive delivers 35,017kNm of torque, said a report.

Mixshield technology is said to be designed for the extreme conditions of tunnelling under the Yellow River. The TBM is currently being dismantled and will then be reassembled at the construction site.

To adapt to the clay, sand and silt geology and the 7.5-bar groundwater pressure under the Yellow River, a Mixshield TBM was selected. Herrenknecht’s Mixshield technology is an advance on conventional slurry technology: the support pressure in the excavation chamber is managed using an automatically controlled air cushion. This means that heterogeneous geologies and high-water pressures of more than 15-bar can be controlled even with very large excavation diameters. An individual, new slurry circuit was designed especially for this TBM, which has been called Shanhe, the report noted.

Jinan, 400km south of Beijing, has a population of nine million and is the capital of the Chinese province of Shandong. The Jinan Huanggang Road Yellow River Crossing Tunnel is the second road tunnel project to cross under the Yellow River in 2024. Tunnelling is scheduled to begin in late 2024.

China Railway 14th Bureau Group Company was appointed as the contractor for the project.

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