The second 15.43m diameter TBM drives below the Yangtze river near Shanghai holed through early last month to complete major excavation of the twin tube transport link.
Herrenknecht’s second Mixshield (S-318) started its drive from Pudong, near Shanghai, to the Changxing Island in the Yangtze at the turn of 2006. The TBM set off on its 7.17km long drive about three months after its sister shield, S-317, which holed through in late May.
Geology comprised sand, clay and rubble, and the drives reached a maximum depth of 65m below the river. JV contractor STEC/Bouygues achieved best progress rates of 26m in a day and 142m in a week, and the bores were finished about a year early. Lining is segmental rings (9+1), each 2m long. The tubes have cross passages every 800m.
The tubes will be fitted with double-decking, roads on top and the lower level will take service and safety installations, and maybe a metro link. The scheduled completion date is a year from now and they will be part of the new link between Shanghai and Chongming Island, the major island in the river.
The client is Shanghai Changjiang Tunnel & Bridge Construction Development and it supplied the TBMs. The shields – the world’s largest – will stay in China though there is no immediate project assignment, said Herrenknecht. The tunnels were design by Shanghai Tunnel Engineering Design Institute (STEDI).
Final breakthrough in Shanghai
