The Analysis Of Ground Surface Settlement And Building Envelope Displacement Caused By Foundation Pit Dewatering

when do deep foundation construction in areas of high water table, we need to carry out precipitation before excavating, and control the grounwater level in order to facilitate the construction and guarantee the stability of the pit.It is usually effective and economical in excavation in soil layer that draining ground water or reducing the difference of water head by light pumping wells or other equipments in order to increase the stability of the pit. However, the lowering of water table will cause uneven settlement of foundation and building envelope deformation which influence to the surrounding environment.In this paper, it is Analysis of the influence of foundation pit retaining structure of ground surface settlement and seepage base on Projeetcase, In this paper, the following work has been done about these problem.First of all, it is introduced briefly that the current development status of foundation pit engineering and points out that foundation pit precipitation problems in this paper,common precipitation method and scope of application.Meanwhile superiority of applying finite element method to problems of seepage and deformation caused by water decreasing in foundation pit is pointed out.Finite element numerical simulation is carried out by Midas Gts software, the model of correct reaction model the process of excavation and dewatering of foundation pit, with the excavation depth increase continuously increase, the deformation of the retaining structure is gradually increasing, and the maximum deformation position near the settlement and deformation of foundation pit retaining structure; increases with the excavation depth increases, the location of the maximum settlement occurred at the16m position; on this basis, considering the state of gap that the seepage flow and without considering the seepage influence of excavation of foundation pit under.Secongly study on the pore water pressure in the excavation stage, velocity contours, and analysis curve variation and variation of pore water pressure, we found that the values of pore water pressure from the underground continuous wall is greatest, and the farther from the wall, the smaller of the impact on the pore water pressure of precipitation excavation; Flow rate contour variation:velocity contours around the excavation face wall are more dense, and the farther from the wall, the sparser of the velocity contoursFinaly, the pit excavation has different influencing factors, respectively, the analysis of the permeability coefficient of the soil and the water level inside the pit changes, at the same time changing the x, y, z direction permeability coefficient, the building envelope, the outside pit table settlement pit uplift impact in the z direction is much larger than the x, y direction; With the increase in the water level inside the pit, pit fieldtable subsidence gradually reduced, or even the phenomenon of surface uplift; horizontal displacement of the supporting structure decreases, and as the water level increase in the occurrence of the maximum horizontal displacement position gradually move up the water line to toe, supporting the maximum horizontal displacement position is gradually increasedtrend.