In the course of the visit to China by the German Minister of Economy and Energy, Sigmar Gabriel, a contract was signed on April 23, 2014, in Kunshan (Jiangsu Province) for the delivery of two tunnel boring machines for a large multifunctional tunnel in Wuhan (central China).
With a population of 10 million, the metropolis of Wuhan is the most important transport hub in central China. By 2017, the metro network of three lines will be extended to seven, from the current 73 km to 215 km in length. 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-m long tunnel alignment runs up to 39.5 m below the water surface in 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 tunneling worldwide.
Shanghai Tunnel Engineering Co. Ltd. (STEC) performing the tunneling. STEC has already realized several large-scale projects very successfully with Herrenknecht equipment, including several large-diameter road tunnels in Hangzhou and Shanghai.