Analysis On Spatial Effect Of The Composite System Of Waterproof Curtain And Retaining Pile

The foundation pit supporting design in high water table areas needs to considertwo aspects of sealing and retaining, so the composite retaining of sealing curtain andretaining pile is a common support measures. But waterproof curtain is onlyconsidered as a groundwater barrier, regardless of its retaining effect. In addition, pitis a space system with length, width and height. In the previous design the pit is oftensimplified as two-dimensional plane strain model which can not reflect the effect ofpit space.In this paper, the two-dimensional plane model considering waterproof curtain,the three-dimensional finite element model considering spatial effects and the finiteelement model considering waterproof curtain and spatial effect are established withthe large general-purpose nonlinear finite element software ABAQUS. The paperstudies the space deformation behavior of the pit and the effect of waterproof curtainon supporting structure deformation and earth pressure distribution. The results showthat:(1) The waterproof curtain can both retain and seal. The more rows of cementmixing pile, the more obvious the earth-retaining effect and the smaller the supportingstructure deformation; with the increasing distance between the waterproof curtainand the pile, the horizontal displacement of the supporting structure is first decreasedand then increased, somewhere in the middle reaches a minimum; the deeper pig, thelarger displacement of the supporting structure and the stronger the retaining effect ofthe waterproof curtain; the insert of the waterproof curtain has little effect on thesupporting structure deformation.(2) The deformation of the supporting structure, soil pressure distribution,bottom heave and surface subsidence have a significant spatial effect. The spatialeffect of the corner is stronger, while the central is weak. The supporting structuredisplacement and passive earth pressure at the pit corner is minium, followed by rapidincrease, reaching a maximum at a certain range of the pit central. Active earthpressure and variation opposite. Bottom heave at the corner and edge of the pit issmaller, while the bottom heave at the middle of the pit is maximum. Surface subsidence is smallest at the corner of the pit, also is the affected area.(3) Spatial effect is affected by the aspect ratio. The smaller aspect ratio, thestronger spatial effect of the foundation. Pit has a critical aspect ratio. When the aspectratio is smaller than the critical aspect ratio, the spatial effect changes more with theaspect ratio; when the aspect ratio is larger than the critical aspect ratio, the spatialeffects can be ignored.(4) Spatial effect is affected by long dark ratio. When the shape of the pit shapeis constant, the deeper the pit, the stronger the spatial effect.(5) The retaining effect of the waterproof curtain and the spatial effect of thesupporting structure are interdependent. Waterproof curtain makes the supportingstructure’s spatial effect weakened. The retaining intensity of waterproof curtain isdifferent at different parts of the pit.