Effects of temperature stress on diaphragm wall of circular deep foundation pit

The effects of temperature on retaining structure of deep foundation pits are related with the thermal-mechanical coupling problem of temperature and stress fields and the interaction of water, soils and retaining structures. Through the back analysis of the measured data of Shin-Toyosu substation deep foundation pit in Tokyo, an analysis method for the effects of temperature fields on retaining structures of circular deep foundation pit is determined, and the changing patterns of temperature fields in the retaining structures are acquired. The research results are applied to the analysis of Shanghai 2010 Expo underground substation. The results show that the inner surface of the retaining structures is exposed to the atmosphere, and that temperature difference occurs between the inner and the outside of the wall due to change of atmospheric temperature. The temperature fields vary in different positions and construction stages. There is no constraint effect of soils in the pit, so the hoop stress of diaphragm wall above the excavation face mainly depends on the water-earth pressure outside the pit, and if temperature decreases, the volume of diaphragm wall will shrink. The diaphragm wall under or near the excavation face is restricted by the soils in the pit, so the hoop stress of the diaphragm wall will decrease when the temperature decreases.