Mega project in China: 17.5-meter TBM for Jinan Huanggang Road Yellow River Crossing Tunnel

The Huanggang Road Yellow River Crossing Tunnel, a two-storey road tunnel with three lanes in each direction, is a major infrastructure project in Jinan, the capital of Shandong Province in eastern China. It aims to connect the urban area on the south side of the Yellow River, the second longest river in the country, with a new state-level strategic pilot zone for free trade, innovation and reform on the north side of the city, greatly improving the transport connectivity of the province's second largest city and ultimately enhancing the economic integration of the region. 

The total tunnel length is 5,755 meters and the mechanized tunnelling section is approximately 3,290 meters long, a segmentally lined structure with an internal diameter of 15.4 meters and an external diameter 16.8 of meters. Excavation is taking place in a geology of clay, silty clay, sand, silt, calcareous nodules and glued sand.

To cope with the geological conditions and groundwater pressures of this project, a Herrenknecht Mixshield (maximum excavation diameter: 17,505 millimeter; currently the largest Mixshield in operation in mainland China; designed maximum operation pressure: 7.5 bar) is being used, with the support pressure in the excavation chamber precisely controlled by an automatically controlled air cushion. This allows heterogeneous geology and high water pressures in excess of 15 bar to be safely controlled, even with very large excavation diameters.

Due to the clayey soil and the potential for clogging, the machine's cutting wheel is equipped with a flushing system. To reduce the need for hyperbaric interventions, a special telescopic camera system is installed in the excavation chamber to monitor the status of the cutting tools and the tunnel face.  

The machine started its tunnelling journey with a launch ceremony on September 1, 2024.