Abstract: In order to solve the problem of long construction period of long shield-bored tunnels where the segment erection is started after the shield boring is finished, the authors propose the "shield boring + segment erection" synchronization technology based on the active control of the thrust vector, and provide an optimization scheme based on the self-compensation calculation method for the missing thrust. Such technology is used on a super-large diameter (14.07 m) slurry balanced shield, which is successfully applied in the Airport Link Line of Shanghai Suburban Railway. The system response data of the shield during the erection of segment ring No. 1 022 are analyzed and conclusions drawn are as follows: (1) The execution accuracy of the pressure of the propulsion cylinders is ±5%, with the phenomenon of short-term response delay. (2) At the moment when the cylinders retract, the total thrust drops sharply before it rises; at the moment when the cylinders extend, the total thrust rises sharply before it drops; the error of the total thrust is controlled within ±3% of the set target value. (3) The shield boring speed is significantly affected by the total thrust, and shares the same trend with the total thrust. (4) The small changes of the thrust vector do not have significant impact on the shield posture, since the shield is surrounded by the soil mass. The construction data of 351 segment rings accomplished in one month by using the "shield boring + segment erection" synchronization technology is analyzed, and the result shows that the adoption of the "shield boring + segment erection" synchronization technology improves the tunneling efficiency by about 27%, compared with the conventional "segment erection after shield boring" technology.

Key words: super-large diameter slurry balanced shield, "shield boring + segment erection" synchronization, shield posture, tunneling efficiency