Abstract:

With the development of urban rail transit works, more and more shield tunnels are built. Due to the tight construction schedule of the shield tunnels, how earlier shield launching can be achieved in the shield launching becomes the focus of the designer and the contractor. The originallydesigned concrete structure of the first and second underground floors of the shield launching shaft of Anhuaqiao StationAndelibeijie Station Section of Line 8 of Beijing Metro is cancelled and reinforced concrete waling is used to replace the originallydesigned steel bracing, and earlier shield launching is achieved. During the construction of the project, the ground surface settlement is monitored. The monitoring results show that the maximum settlement of the ground surface surrounding the shield launching shaft is 6.42 mm, and the settlement of the utility lines is less than 1 mm. The practice shows that reinforced concrete waling can be used to replace the originallydesigned steel bracing, so as to achieve earlier shield launching.

Key words: Beijing Metro, shield launching shaft, reinforced concrete waling, steel pipe bracing