Numerical Analysis of Deformation of Deep Foundation Excavation in Soft Clay Considering Influences of Time-effect

Abstract

The traditional foundation pit design generally only considers the transient deformation. However, the excavation deformation characteristics of deep foundation pits in soft soil layers not only consider the small strain characteristics during the excavation, but also consider the time effect. Taking a foundation pit in Wenzhou as the engineering background, based on the HSS model and the SSC model, PLAXIS finite element software was used to simulate the excavation process of the deep foundation pit. The deformation characteristics of retaining structures and deep excavation are compared and analyzed. Calculations prove that: The deformation rules of the foundation pit with the time effect is basically the same as those without the time effect. During the excavation of the foundation pit, the horizontal displacement of the diaphragm wall, the ground settlement and the foundation upheaval calculated based on the SSC model are larger than those calculated based on the HSS model. The calculation results based on the SSC model show that after the completion of the excavation, the deformations of the foundation pit continue to increase with time, showing a rheological effect. The conclusion can provide theoretical guidance for the construction of foundation pit excavation in Wenzhou area to ensure the safe implementation of the construction process.