Abstract:Time-space effects have been validated with a lot of soft soil deep foundation pits. Step construction during the excavation is an effective way for the application of the theory of time-space effect,though those applications are somewhat experiential. A method to analyze behaviors of deep foundation pits considering the effects of step-by-step construction is proposed. A 3D finite element program based on the model is developed. The method is used to analyze the deformations and inner forces in the retaining piles and the struts of a typical excavation case. The numerical results are compared with the results that not considering the construction effects. It is also proven that step construction is an effective way to control displacement of deep foundation pits in soft soil. Finally,the method proposed here is used to analyze an actual deep pit project in Hangzhou. The analytical results are compared with the measured data. It is indicated that the suggested method can be well used to simulate the complex excavation process of foundation pits.