Abstract: Axis deviation easily occurs during shield tunneling in soft clays due to the overlarge settlement, while adjusting the slope ratio of tunnel difficulty, even affecting the running speed of trains during the operation period. Grouting uplift is a solution to axis deviation. In order to not cause structural failure, not affect construction period, and improve the tunnel line shape, a case of uplifting practice for overall tunnel structure in an inter zone with overlarge settlement of Ningbo metro construction is studied in this paper. Through the analysis of the geological condition, structure calculation, grouting process research, lower part of tunnel structure grouting, internal support, real-time monitoring, real-time ideas adjustment, the process of grouting slurry adjustment timely; and the fine management, the integral structure of tunnel is uplifted about 3cm without causing any damage; so that the tunnel line shape is improved effectively. The engineering practice shows that the grouting process and internal support play an important role to uplift stage general ring structure safety; slurry choice is very important to late stability. And by the practice, control measures for uneven subsidence of tunnel construction in soft clays are explored to provide references for other similar engineering and shield tunnel uplift designing.

Key words: soft ground, shield tunnel, tunnel structure, grouting uplift