Herrenknecht giants reach their targets in Shanghai

The Herrenknecht Mixshield S-318, one of the two largest tunnel boring machines (TBM) in the world with a diameter of 15.43 meters, reached its target shaft on the Yangtze river island Changxiang on September 5, 2008. But not only this giant showed a top performance, excavating an almost 7.5 kilometer long tunnel tube in highly water-bearing construction ground in only 20 months. A good three months before, on May 28, 2008, the identical Herrenknecht Mixshield S-317 reached its target shaft with great precision. Using the two high-tech giants from Schwanau, the shell of the two parallel running large diameter tunnels, which are scheduled to be opened for car and subway traffic for the 2010 World Exhibition, could be completed 10 and 12 months ahead of schedule respectively.

At the beginning of September, the red carpet was rolled out for politicians and construction experts when Shanghai's vice mayor, Jun Shen, proudly announced the successful completion of tunnelling at the “Shanghai Yangtze Under River Tunnel”. Following final completion, both tunnels will accommodate a three-lane road on the upper level and a subway line on the lower level. The completion of tunnelling work ahead of schedule provides the ideal conditions to open the tunnel on time for the 2010 World Exhibition in Shanghai.

A construction site team that did a perfect job and the strong performance of the two Herrenknecht Mixshields were the basis for quick and safe tunnelling on this superlative project. With an overburden of up to 65 meters, the machines burrowed their way through sand, clay and groundwater with water pressures of up to 6.5 bar. Weekly tunnelling performances of up to 142 meters of constructed tunnel were reached, performance per day was up to 26 meters. The teams operating the TBMs directed the 2,300 ton and 125 meter long colossus with highest precision. On a route of 7.5 kilometers, they deviated only 2.7 centimeters from the ideal line. Now, the two tunnels of the "Shanghai Yangtze Under River Tunnel" connect the Shanghai district of Pudong with Changxiang island on the Yangtze river. From 2010 onwards, the combined road and subway tunnels will reduce the traveling time between Shanghai and the Yangtze river island Changxing from 1 hour to 20 minutes and replace the existing ferry connections.

The two breakthroughs at the “Shanghai Yangtze Under River Tunnel” are an important milestone in mechanized tunnelling. As reference projects, they demonstrate that the challenges of structural engineering for extremely large tunnel profiles can be mastered with bravura when it comes to construction times, budget and safety using the technical know-how of mechanized tunnelling. They constitute an impressive success for both the Changjiang Tunnel & Bridge Construction, Ltd. and the partnership between Shanghai Tunnel Engineering Co., Ltd., Bouygues TP and Herrenknecht, the technology and market leader in mechanized tunneling from Schwanau (Southern Germany).


Contact:
Herrenknecht AG
Schlehenweg 2
77963 Schwanau
Corporate Communication
Mr Achim Kühn
Tel.: +49 (0)7824 302-540
Fax: +49 (0)7824 302-473
E-mail: pr@herrenknecht.com
Web: www.herrenknecht.com