FINITE ELEMENT ANALYSIS OF TIME-EFFECT ON DEEP EXCAVATIONS IN SOFT CLAY

In soft clay,because of its consolidation and creep,time effect is detectable in deep excavation.In this paper,finite element method coupled with Biot consolidation theory is used to research the behavior of deep excavation.The first linear spring is used to stimulate the consolidation.The elastic module is considered about the influence of the excavating stress-path and stress-history.The other part of the model(KELVE model) is used to stimulates the creep of clay.Its two parameters are gained approximately through partly analyzing the real deformation in the engineering.Then the deformation associated with whole excavation is analyzed step by step during the process of excavation.Normally-consolidated and saturated clay is assumed,and plane strain problem is considered.When analyzing a real example of deep excavation in saturated soft clay,the curve of the wall horizontal displacement computed is quite inosculated to the field measured ones,so it indicates that this finite element code is good for stimulating time-dependent behaviors of excavation.The reason why there are some curves not-well-inosculated is also explained.The sedimentation rule of post-wall ground surface is provided in addition.