Study On Application Of Finite Element Method In Foundation Pit

Because of various foundation conditions and complicated entironment, some uncertain factors consist in the constructing of foundation pit, therefor it is difficult in establishing a suit of standard mode for the design and constructing of foundation pit project, or settling all potential movement in constructing of foundation pit project with a suit of narrow theory and calculatinal method.The FEM theories in foundation pit are various, but each of them is of somewhat limitation, and will meet a lot of difficult in calculating. In the first part of this paper, the current calculational methods in common use are introduced,and the main FEM theories are studied, and the characteristic of each theory are analysed, some corresponding improvement is maked. In the second part, how to apply the FEM theories in foundation pit project to guide design and construction is studied,and two main application methods are advanced.⑴Calculate and Analyse. Simulate and Calculate the foundation pit project with the bar system FEM or the planar or spacial finite element method. The pile building enclosure with two or three bracing pieces and the gravity retaining wall are particularized as example in this paper. From the antithesis with datum practically measured, it indicates that the FEM which is adopt by this paper is logical and feasible. In addition, in this paper, the calculate results of incremental calculation method and total calculation method are compared; the infection of the pile stiffness,the elastic modulus of soil and pile,the excess load,the soil character to building enclosure are discussed, and some useful conclusions are found.⑵Optimization Design and Dynamic Contrary Analysis. According to the design principle of safety and economic, this paper has studied the implement of optimization design for the support construction in foundation pit with the total amount of material as object function, and the pile diameter,the pile length,the supporting location and the supporting diameter as the design variables. Aside, the dynamic contrary analysis on the parameters is carried on with the optimization method, and the forecast is made, the result is satisfying。...