Abstract：There are many hot issues about solid-fluid coupling during the construction of large-scale shield tunnel beneath river or sea. The solid-fluid coupling effect on segments internal force in the process tunnel excavation is the main issue. According to the continuum theory，finite element analysis is adopted for a drain tunnel project crossing Yangtze River in the downtown of Chongqing City. Study on segment internal force distributing by two methods is carried out. One is considering water load combined with soil load，another is considering coupled effects. The result is verified by in-situ data. The calculation results show that internal forces of segments are different during shield tunnel construction. The internal forces of segments reach maximum values at the time of assemble completed，while the value will decrease for the long-term groundwater seepage. Mechanical characteristics of segment and structure are also studied，and shield tunnel construction parameters have close relationship with solid-fluid coupling. The achieved results can provide references to the design and construction of similar engineering cases.
