Three-Dimensional Performance of an Over-Size Complex Excavation in Shanghai

This paper presents an over-size complex excavation project. In order to control retaining wall lateral displacement and associated ground movement within specified limits, this project was constructed using the method of "central part by bottom-up method and peripheral part by top-down method". A comprehensive monitoring system was installed on this project to reduce risk and study the deformation behavior of such excavation. Wall displacement, ground surface movement and bottom heave were separately measured and analyzed during the excavation. Field observations indicate that the wall lateral displacement is correlated with the zoned excavation and floor slabs installation sequence. The ground surface settlement near the corner of the excavation is less than that near the center, which corresponds to those reported in the literature. The behaviors of the diaphragm wall and ground surface settlement are affected by the "creep effect".