The two Mixshields with an excavation diameter of 15.76 m to be supplied by Herrenknecht will cross under the Yangtze River in Wuhan and create a twin-bore double-decker tunnel. A three-lane road will run on the upper deck, with metro line 7 below.

The 2,590 meter long tunnel alignment runs up to 39.5 meters below the water surface in extremely complex soil. On the one hand, a high water pressure of 5.3 bar must be dealt with. In addition, the tunnel runs through varying geological formations, partly completely sand and clay, partly a mixed geology with mudstone, conglomerates and sand.
With its size and multipurpose use the construction represents a major reference project for mechanized tunnelling worldwide.

The 10 million metropolis of Wuhan is the most important transport hub in central China. By 2017 the metro network of 3 lines will be extended to 7, from the current 73 km to 215 km in length.

In the past customer Shanghai Tunnel Engineering Co., Ltd. (STEC) has already realized several large-scale projects very successfully with Herrenknecht equipment, usually months ahead of schedule. These include several large-diameter road tunnels in Hangzhou and Shanghai.