Abstract:

The downtop excavation method, with large construction risk, could be chosen when the construction scheme is short. The design, construction and management have to be controlled so as to guarantee the safe construction and to reduce the construction risk. In this paper, the comparison is made among the construction methods of ancillary works of mined Metro station on Line No.7 of Beijing Metro in terms of advantages and disadvantages; and then the construction technology and management technology of downtop excavation method are systematically studied. Finally, the construction scheme of downtop excavation method and the rules of ground surface settlement are analyzed. The monitoring data show that the safe construction has been guaranteed; the influence of downtop excavation on surrounding environment has been minimized and the ground surface settlement has been brought under effective control.

Key words: Metro station, inclined section, downtop excavation method, risk management and control