Research Of Foundation Pit Support Structure And Surrounding Soils Deformation Under Different Bracings Programs

Based on the engineering survey and field investigation,this paper uses PLAXIS software of three-dimensional finite element analysis(FEM)to analyze the deformation and deformation of the supporting structure,and the settlement pattern of the surrounding soil,Based on the numerical model,the displacement of the supporting structure and the law of soil settlement caused by excavation are studied respectively.Then,the numerical model is established,and the model is verified by the displacement of the supporting structure and the surrounding soil settlement.Through this model,a variety of supporting arrangement scheme is studied,and the original design scheme is optimized to control the deformation of the foundation pit.The following results are obtained:(1)Through the monitoring of the displacement of support structure and the settlement of foundation pit,the data were analyzed and analyzed.Only under the action of the top support,after the foundation pit excavation,the horizontal displacement of the support structure appears near the bottom of the foundation pit excavation.The horizontal deformation type of the whole supporting pile is the "internal convex" The minimum horizontal displacement of the pile is located at the bottom of the supporting pile.The settlement of the soil outside the foundation pit is "U"-shaped.The maximum ground settlement is located at the measuring point 8 ~ 14 m away from the excavation.(2)The horizontal support arrangement has a great influence on the settlement of the soil outside the foundation pit and the horizontal deformation of the support structure.The adjustment of the horizontal support scheme can well control the deformation of the foundation pit,and the control effect is obvious.For a horizontal support,The middle of support pile can better control the deformation of foundation pit.For two horizontal supports,the top and middle of support pile can better control the deformation of foundation pit.(3)By optimizing the level of horizontal support,enlarging horizontal support section can effectively control the deformation of foundation pit support structure.Which support the pile at the top and middle of the horizontal support cross-sectional size enlarged to 1.6 times or more to meet the requirements of a security pit,and more economical.