Abstract: In order to study the influence of Tjoint connecting passage construction with mechanical pipe jacking method on surrounding environment, field monitoring and theoretical calculation analysis are carried out based on the project of Wuxi Metro Line 3, and the variation law of stratum settlement is investigated. Circular monitoring points are set on the ground around the connecting channel, and the monitoring results show that: (1) The ground surface transverse settlement is large above the center position of the passage but small aside, and the transverse displacement variation is asymmetric due to the influence of main tunnel inclination etc.; (2)The ground surface longitudinal settlement forms a groove in the middle and a relative bulge in the center possibly due to the road green belt, and the ground surface rises slightly along construction direction. Based on the numerical simulation analysis, the variation law of ground surface uplift and subsidence under the above specific conditions is verified, furthermore, through numerical experiments, the whole process of the construction of the main tunnel in the early stage and the subsequent connection channel is simulated. The effects of different jacking forces on ground surface uplift and subsidence are discussed, which shows that, the larger the jacking force is, the more obvious the uplift is in front of the construction. In theory, a full period settlement displacement model with peck curve superimposed on the vertical and horizontal directions is established. The characteristics of the transverse settlement trough described by the model are similar to the numerical solution of the whole construction process mentioned above, but the longitudinal settlement characteristics are not similar, which need to be further verified. On the whole, the construction method has slight influence on the ground settlement displacement, and the construction safety is controllable.

Key words: metro connecting passage, Tjoint connecting passage, pipe jacking method, ground settlement, monitoring, numerical analysis, settlement displacement model