Abstract:

Large diameter (11.58 m) slurry balance shield is used for boring North Huancheng Road underground expressway tunnel crossing underneath existing ShanghaiHangzhou highspeed railway bridge and culvert. Considering the complex environment the shield tunnel located and the safety of the running of highspeed railway, the longitudinal and circumferential structural responses induced by shield tunneling are monitored by means of longitudinal and circumferential rebar stressmeter. The monitoring results show that: 1) The longitudinal and circumferential differential settlement rates are 0.20‰ and 0.30‰, which can meet the requirement of safe construction of railway. 2) The thrusting force of shield varies with the change of shield attitude and has a significant influence on segment force and displacement of bridge and culvert; the longitudinal axial force of the segment top is larger than that on the segment feet; the circumferential bending moment of the segment waist followed by that of the segment top and that of segment feet; and the circumferential bending moment of the segment shoulder is the smallest. The study results show that the monitoring of the shield tunnel structure is important as well.

Key words: tunnel, large diameter slurry shield, underneath crossing, highspeed railway bridge and culvert, displacement monitoring, settlement regular, interaction