Abstract:

The influence of deep foundation pit construction on adjacent shield tunnel in floodplain area of the Yangtze River is studied so as to verify the feasibility of the comprehensive emergency protection measures adopted. According to the monitoring data collected during previous construction phase, it is showed that the main influencing factors of deformation of shield tunnel structure are dewatering, lateral unloading and additional loading of deep foundation pit. The influencing factors are quantitatively analyzed by modified traditional method; and then relevant construction control technologies and reinforcing technologies are adopted. The comparison between monitoring data before and after carrying out countermeasures shows that the control of dewatering, unloading and additional loading are the keys to design and construction of deep foundation pit adjacent to shield tunnel and the comprehensive emergency protection measures adopted are rational and effective.

Key words: floodplain area of Yangtze River, deep foundation pit, shield tunnel, modified traditional method, emergency protection