| Because of the soft clay with large rheology,high compression and strongcreep.Makes the envelope structure and ground surface deformation in the excavationprocess will change over time increase when subway foundation constructed in theweakness of the clay areas.If you can not design the construcion parameters reasonablethe deformation will be difficult to control the permitted level of security.In thispaper,based on one station foundation pits of NO.2subway in Wuhan city,thenumerical simulation model which consider the excavation time-effect is establishedwhich used the SSC constitutive model of soil.In this model,taking into account thefactors mentioned above on the deformation and settlemnt.During the deep foundationpit excavation in soft clay soil areas,the laws of time and deep pit supportingdeformation in consideration of different factors are discussed and analyzed.Drawsome conclusions which can be used for guidance in the areas of similar soilconstruction and design work.1.The excavation time has a great impact on displacement field of foundation andinternal force.In this paper,the deformation of this period is divided into twostages.The deformation of the wall is developed rapidly in first stage.The deformationof diaphragm wall is developed stablly in second stage.2.The laws of pit deformation without support.The pit deformation of withoutsupport during excavation end within2hours occupy more than90%of total nosupport deformation.The first days of without support deformation occupy more than95%of the total no support deformation.3.The effects of pit deformation about overloading location.A greater impactwhen the overload from the foundation pit edge less than10m,this effect will beweakened when the distance is greater than30m. 4.The Variation laws of the upheaval of the foundation pit with depth andexposure time with support.With the increase of depth of the deformation rate of pitbottom uplift is increasing.And the time-effect of the bottom uplift is more and moreobvious. |
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