Anotace:
This paper takes Guangzhou Haizhu Wan shield tunnel project as the background to study the key technology of large-span pile foundation replacement construction under the condition of super-large diameter shield. Research on key technology of large span pile foundation replacement construction under super-large diameter shield conditions was carried out. Formation of spanning 20.8 m large-span buttress structure with buttress piles, double buttress beams and bearing platforms, active buttressing, and truncation of existing pile foundations construction methods. Research focused on the active buttressing phase, which directly affects the deformation of the superstructure. At the same time, the existing building settlement, tilt and stress-strain of the joist were monitored during the joist construction. It shows that the maximum settlement value is -6.1 mm, the overall uneven settlement does not occur, and the monitoring results do not exceed the warning value. Monitoring results show that the large-span prestressed double-beam buttress pile foundation can effectively control the settlement of the superstructure, and have good construction effect.