Abstract:

The potential risks of longdistance boring of shield in sandy strata of Phase 2 of Zhengzhou Metro Line No. 2 are analyzed. The adaptability design of the shield machine is carried out in terms of wear resistance and cutterhead opening rate according to the mechanical parameters of sandy strata before shield boring. The rational ground conditioning methods and grouting parameters are decided by field test during shield tunneling. The results show that the wear resistance and the shield boring efficiency in sandy strata have been improved and the ground surface settlement has been controlled by adopting abovementioned technologies.

Key words: Zhengzhou Metro, sandy strata, longdistance boring of shield, shield design, ground conditioning, grouting parameters