Two Herrenknecht Mixshields with an excavation diameter of 15.76 meters for crossing under the Yangtze River in Wuhan have built a twin-tube, two-story tunnel. A three-lane road runs on the upper deck, with metro line 7 below. The launch of the first of the two TBM giants was celebrated in the presence of political dignitaries on April 27, 2016.
The cutting wheels of the large machines for Wuhan are accessible for fast and safe changing of the cutting tools.
The 2,590 meter long tunnel alignment runs up to 38 meters below the river surface in extremely complex ground conditions. On the one hand, high water pressure of 5.3 bar had to be dealt with. On the other hand, the tunnel runs through different geological formations, partly entirely sand and clay, partly a mixed geology of argillite, conglomerates and sand.
The two Mixshields are equipped with accessible cutting wheels. Thanks to this sophisticated concept, the cutting tools can be changed quickly and safely under atmospheric pressure. The cutting wheels were manufactured in Herrenknecht's Schwanau plant and transported to China, where at customer Shanghai Tunnel Engineering Co., Ltd (STEC) factory assembly was carried out.
High wear of the cutting tools and clogging of the cutting wheel lead to a longer break of the project. The jobsite team and the Herrenknecht specialists worked together on a solution with adjustments of the cutting tools as well as the flushing at the center of the cutting wheel.
Successful breakthrough in April 2018
In mid-April 2018 the first of the two machines crossed the finish line and in late May the second reached its target shaft. Despite the difficult geological conditions, the miners achieved weekly best performances of 94 meters with each of the machines.
On October 1, 2018 already, the structure was ceremoniously inaugurated and opened to traffic.
Projekt Highlights
The 10 million inhabitant metropolis of Wuhan is the most important regional and national transport hub in central China. A highly efficient subway network, currently consisting of nine lines with a total length of 288 kilometers, carries between 2 and 3 million people a day through the city. Further extensive expansion and new construction will help keep up with population growth.
Wuhan Sanyang Lu Yangtze Tunnel set the benchmark in terms of collaboration between Herrenknecht and STEC. Though the difficulties that confronted us during tunnelling seemed insuperable, we made the final breakthrough possible in June 2018, based on our technical expertise, project experience and our determination to succeed.
Zhang Yan, Chairman of STEC
| Column 0 | Column 1 |
|---|---|
| Project | Wuhan Metro Line 7 SanYang Road River Crossing, China |
| Client | Wuhan Metro |
| Contractor | Shanghai Tunnel Engineering Co., Ltd. |
| Year | 2016 - 2018 |
| Application | Metro and three-lane road on two levels |
| Geology | Heterogeneous ground: Sand, clay, mudstone, compacted conglomerates |
| Tunnelling lengths | 2578m + 2,590m |
| Machine data | 2x Mixshield: Excavation diameter: 15,760mm Lining Method: Segmental lining Cutterhead power: 5,600kW Torque: 27,720kNm |
We are ready!