Abstract:A field analysis is carried out on the deformation of a multi-supported strip municipal deep foundation pit with 17.5 m depth in Shanghai. It shows that the lateral displacement of its retaining wall is distributed in a typical bow shape along the depth and there is a certain kick deformation, which has a significant impact on the lateral retaining wall displacement of shallow pit in the affected range of "pit in pit". In design, the insertion ratio of the outer ramp retaining wall can be increased, and a concrete transmission belt can be set between the outer retaining wall of ramp and the first retaining purlin of deep pit, which can effectively reduce the outer excavation deformation of ramp. At the same time, The value of the relationship between the anti-hump safety factor and the maximum lateral displacement is within the classical statistical range. The ratio of the maximum lateral displacement to excavation depth of the retaining wall is basically between 0.30%~0.77%, which is between the second-level and third-level environmental protection control lines. The distribution curve of surface settlement behind the wall is more in line with the standard prediction curve of foundation pit in Shanghai. Its ratio to wall lateral displacement is basically between 0.4 and 2.0, and its average value is 0.80. The average value with no-ramp region is relatively large. The rebound of column piles has the obvious spatial response characteristics. The rebound amount in the middle of the foundation pit is about 1.3~1.45 times of the average value and 2 times of the rebound amount of column piles on the side of the foundation pit. The spatial response characteristics are more obvious.
