The Deformation Analysis Of Foundation Pit Based On Coupling Of Fluid And Solid Theory On Soft Soil Area

In recent years, geotechnical workers at home and abroad has made a lot of outstanding achievements in the excavation engineering research, and has accumulated lots of useful experience of pit design and construction. With the accelerated development of urban modernization, high-rise buildings of the city are constantly becoming higher and followed by higher demanding of excavation stability. Especially in coastal areas,many tall buildingscan only be built on soft soil, hence we need to take effective measures to reduce the impact of this complex geological conditions on foundation stability and the surrounding environment.A very significant problem in soft soil area is the problem of groundwater.Excavation dewatering need to be done during excavation when the excavation surface is below the water table precipitation, becausegroundwater level change causesthe change of soil seepage and stress field, while seepage field and stress field will influence pit deformation and internal force of retaining structure. Thus, the study of fluid-structure coupling has important theoretical research value and engineering application value.Firstly, by means of a simple engineering example, the writer analyzes it respectively with MC model, HS model and concludes that the HS constitutive model is more suitable to simulate the loading-unloading process in excavation process. Secondly, the writer gets basic equations of fluid-solid coupling based on the seepage theory and simulate rainfall seepage field of Shishan Science &Technology Museum excavation engineering. Using numerical software PLAXIS,the writer builds two pit models.One of the models is based on the total stress method without consideration of the role of water, the other is to consider fluid-structure coupling model based on effective stress method. The writer analyzes the displacement of the wall, basement uplift value, surface subsidence and wall internal force,and puts forward the corresponding control deformation of foundation pit according to the analysis results.