Three-dimensional numerical modeling of a deep excavation adjacent to Shanghai metro tunnels

Abstract

Due to rapid construction and limited urban area in Shanghai, some deep excavations are very close to the existing metro tunnels or sensitive superstructures. Therefore the safety of the adjacent tunnels and surrounding structures become an important issue during design and construction of these deep excavations. This paper presents a 3D finite-element modeling using the finite element analysis program ABAQUS for an oversize deep excavation in Shanghai soft deposits. The excavation is the excavation of the north square underground shopping center of Shanghai South Railway Station. Two cases of numerical analyses assuming anisotropic and isotropic soil stiffness respectively are conducted. The estimated wall deflection and ground movements are compared with the field monitoring results. It is found that soil stiffness anisotropy has a significant effect on the accuracy of prediction of the diaphragm wall deflection and the ground movement around excavation for the oversize excavation in Shanghai soft deposits. The calculated ground movements of the anisotropic case agree well with the field measurements. © Springer-Verlag Berlin Heidelberg 2007.