The FEM Analysis And Optimization Design Research Of Soil Nailing Bracing For Foundation Pit

As a efficient,convenient,cheap retaining technique, soil nailing technique is widely used in the foundation pit engineering at present.But the mechanism and retaining theory of it hasn't been understanded deeply by engineers yet.As a provisional establishment,it will be wasteful if its design of the supporting structure is too conservative.On the other hand,if the economic benefit is just focused on and the stability of foundation pit is neglected,it will lead to some engineering accidents and the more investment waste.A highly-efficient method to resolve this problem is to find a optimization design of soil nail bracing.Base on the study of the CCCC Fourth Harbor Engineering Company"The study on monitoring technique in long open-trench tunnel with big cross section",this paper analyzes the rule of soil nail axial forces and foundation pit deformations change in each construct stage of excavation. For this purpose, the Midas/GTS software is used to calculate the stress and displacement of foundation pit engineering in each construct stage for the typical section.After that,the GA is used to find a new optimization design of soil nail bracing.Then the optimization design of soil nail bracing is evaluated by the numerical simulation.It's proved that the optimization design has a feasibility to implement.The study in this paper makes the contribution for the research on theory of soil nailing bracing and suplies some reference for those similar engineerings.(1) In the construction process of foundation pit,the axial forces of soil nails is in shape of spindle．and when the excavation finished,the soil nails in the middle of foundation pit have larger axial force．Corresponding,the horizontal displacement is larger．(2) It'S more advantageous for GA in soil nail optimization design,and it will be convenient to solve the actual problems in MALAB by using GAOT tool box．(3)The optimization design result is proved that it saves the costs,maintain the stability of the foundation pit and is helpful to deformation control by numerical simulation．...