Design and Performance of Large Excavations for Shanghai Hongqiao International Airport Transport Hub Using Combined Retaining Structures

摘要

As an important add-on to Shanghai Hongqiao International Airport, the Shanghai Hongqiao International Airport transport hub is the biggest transport center in China. The transport hub consists of interchange stations for five different metro lines, two traffic squares, a high-speed railway station, and a station for the maglev train connecting the Hongqiao and Pudong international airports. The excavation area of the project reached up to 350,000 m(2) and the excavation depth ranged from 9 to 29 m. A combined retaining system, which consisted of slope excavation, a gravity retaining wall, and a diaphragm wall, was adopted. Sloped excavation and a gravity wall were used for the shallow excavation area, while a diaphragm wall braced by two levels of concrete struts was adopted for the deep excavation area. An extensive instrumentation program was carried out to monitor the performance of the large deep excavation and hence verify the design work. The deformations of the combined retaining system during and after the construction were recorded and analyzed. Based on the field monitoring results, the combined retaining system adopted in this project proved to be feasible for such large and deep excavations in the soft Shanghai soils. (C) 2014 American Society of Civil Engineers.