Abstract: To solve the problem of segment uplift during the very-large diameter shielded tunnel excavation, a three-dimensional finite element model considering the time-varying characteristics of grout is established based on the Jiangyin-Jingjiang Yangtze River Tunnel project. The commercial finite element software ABAQUS (2016) was used, and the simulation results were compared with the monitoring data of the actual working conditions to calibrate and validate the model. Combining the simulation results, the effects of geological compressibility, grouting pressure magnitude, and grouting pressure duration on segment uplift were analyzed. The sensitivity analysis method was introduced to evaluate the sensitivity of each factor on the segment uplift. The results show that the enhancement of geological compressibility, the increase of grouting pressure, and the increase of grouting pressure duration will aggravate the phenomenon of segment uplift in shielded tunnel excavation. The sensitivity of each factor to segment uplift is in the order of geological compressibility, duration of grouting pressure, and grouting pressure magnitude. Engineering-oriented control measures are given from the perspective of practicality.

Key words: Shielded Tunnel, Segment Uplifting, Parameter Study, Sensitivity Analysis