The active earth pressure acting on the flexible retaining wall during excavation of foundation pit is analyzed. The retaining wall is assumed to deflect as bulge shape that the maximum displacement is located at the excavation surface. The slip surface is assumed as a plane through the wall toe. A general slip surface angle is deduced by considering excavation depth and support of foundation pit. The active earth pressure distribution

lateral soil force and its application are obtained based on the horizontal thin layer analysis method. The results show that the theoretical results are consistent with the measured results. As the excavation depth increased

the angle of the slip surface decreased; the influence scope and the active earth pressure are enlarged; the influence on the position of resultant force is small. When the excavation depth decreases

the soil friction angle and soil wall friction angle increase

the nonlinear distribution of active earth pressure becomes more obvious; the resultant force decreases; and the distance between the application point of resultant force and the wall toe increases.