To know well the impact on the deformation of underground diaphragm wall caused by soil excavation

centrifugal model tests reflecting Shanghai soft soil creep effects were designed

and finite element was used to calculate the deformation of underground diaphragm wall caused by different excavation timeline

sequence and width based on the top down construction method in the deep and large foundation pit of Shanghai Expo axis underground complex project. Centrifuge model tests and monitoring data indicate that the results of numerical calculation are approximately close to the horizontal displacement of the underground diaphragm wall measured in site

which reflects the deformation behavior of excavation. The results show that remained berm and middle plate have good control over the deformation of underground diaphragm wall. Most part of underground diaphragm wall deformation caused by soil creep occurs after the remained berm is excavated. So in order to decrease the deformation of underground diaphragm wall

it would be useful to conduct plate structures as soon as the remained berm is excavated. The excavation width of remained berm in the north part is less than that in the south part. It will be advisable to finally excavate the remained berm where there are protected objects nearby.