ANALYSIS OF DEFORMATION IN CONSTRUCTION STAGE OF STEEL-CONCRETE-STEEL COMPOSITE IMMERSED TUNNEL IN SHENZHEN-ZHONGSHAN LINK

The steel shell-concrete composite structure, which is prefabricated by pouring concrete into the empty steel shell, is adopted in the immersed tunnel of Shenzhen-Zhongshan Link. To evaluate the overall deformation of the immersed tube after construction, a thermal-structural sequence coupling analysis framework was proposed. Based on the ANSYS APDL and UFPs modules, the refined temperature field model that considers the degree of hydration, solar radiation, and ambient temperature variation, and the structural model that considers concrete hardening and shrinkage were established. The reliability of finite element models was verified by comparing the analytical temperature and strain results of the full-scale tube with the monitoring data. On this basis, the overall deformation mode of the immersed tube and the influence of temperature effect, concrete shrinkage and dead weight on the overall horizontal, vertical and vertical deformation of the immersed tube were studied. The results show that the temperature field of the tube during the construction is time-varying and spatially distributed. The temperature of the side of compartments shows periodic fluctuations due to ambient temperature variation and solar radiation, but the peak temperature of the middle part of compartment is controlled by the concrete hydration itself; the roof of the tube shows contraction in the lateral and longitudinal directions, and deflection in the vertical direction. The floor of the tube shows no significant deformation in the lateral and vertical directions; the influence of solar radiation on the structural temperature field is more significant than the daily temperature variation, so the solar radiation is recommended to be considered in predicting the temperature peak, and the daily temperature variation can be simplified by using daily average temperature; the temperature effect and material shrinkage have a significant impact on the overall deformation of the tube in the lateral and longitudinal directions. The proportions of the deformation in the lateral and longitudinal directions caused by the dead weight are 44.3% and 11.7%, but the proportion in the vertical direction is 92.5%. Therefore, the temperature effect and material shrinkage cannot be ignored in the analysis of the lateral and longitudinal deformation; the analysis method in this paper can be applied to the prediction and evaluation of the temperature effect of mass concrete structures.