On April 26, 2022, a 15.02-metre-wide Herrenknecht Mixshield began excavating the "Yangtze River Crossing Tunnel" project under the watchful eyes of Wuhu city leaders. This is the first crossing under the Yangtze in Anhui Province.
While the Yangtze River is 930 meters wide at the designated point, the XXL Mixshield has to drive a total of 3,950 meters of tunnel. On three levels, one above the other, the large diameter of the tunnel provides space for ventilation systems, a three-lane roadway, as well as a service and escape channel below, together with cable lines. Under the river bed, an overburden of only 14 meters is expected.
Geologically, the tunnel builders can expect silty clay and chalky clay, chalk, weathered and muddy siltstone, as well as weathered quartz sandstone and tuff conglomerate, separated by a 15-metre-strong fault. The quartz sandstone in particular is rubbing against the cutting tools with strengths of up to 113.4 MPa, which can be monitored with the proven DCRM system and changed in time under normal pressure. Gas deposits can occur in the tunnel section, particularly in the clay layers. Special sensors detect these immediately. Other features include the extendable main drive, a rock crusher optimally adapted to the conditions and a guidance system from Herrenknecht subsidiary VMT.
