ABSTRACT
Freeboard adjustment is an important process after prefabricating immersed tube tunnels. It directly relates to whether the pipe joints can float and sink safely. Given the traditional pouring of concrete on the top of the pipe joints to adjust the freeboard, large amounts of concrete waste and high construction costs are caused. Based on the Yuliangzhou section project of the Xiangyang east-west axis road project, the mathematical model of freeboard adjustment based on the counterweight method is established, and the changing relationship between the moment of the counterweight of the pipe joint and the freeboard at different positions of pipe top is analyzed. Moreover, the combination of ballast concrete pouring in advance in the inner lane of the pipe, water bag weighting in the middle pipe gallery, and sandbag leveling are adopted for freeboard adjustment. The results of on-site freeboard adjustment show that the freeboard after adjustment meets the requirements of floating and sinking on-site and strongly supports the supporting project.
