Numerical Simulation Of Cement-Soil Pile And Soil Nailing Supporting For Foundation Pit Excavation

Soil nailing supporting technology is one kind of rapid, simple, economic, safe and reliable construction, extensive application in underground engineering. Especially in the foundation pit supporting projects, nearly half of all projects are adopting soil nailing support technology, however, some of its own limitations limit the development of this technology. In order to bring the technology to the building engineering, a variety of composite soil nailing supporting technology are gradually developed to strengthen the pure soil nailing support, and some good results have been obtained.Composite soil nailing support technology keeps the advantage of the soil nailing support technology, make up for the soil nailing support technology and many technical flaws and application limitation have been settled. All in all this technology have been made great progress. But during the composite soil nailing support system in the excavation process, the mechanical deformation of the foundation pit is influenced by many factors, can meet many complicated cases. especially, the composition of composite soil nailing support system single coordination in working mechanism is still unclear, and there are not enough necessary analysis methods, and the failure to form a complete theoretical system stile exist, systematic deep theoretical research and application technology research work need to be conducted.Based on the current composite soil nailing current research and engineering application, in view of soil nailing stability analysis and stress mechanism, deformation, with theoretical study and numerical simulation method combined, foundation pit excavation deformation, surface subsidence, den rebound displacement of compound action carries of the cement-soil pile and soil nailing support structure system are analyzed and summarized. According to the commonly used Lizheng foundation pit excavation design software, results and analysis between them are calculated and contrasted, thus some foundation pit bracing design suggestion and opinion are studied. Main job achievements are as follows:1) Stirring pile composite soil nailing emergence and development are explained and its advantages and limitations are pointed out.2) Structure reinforcing supporting mechanism of each part in the stirring pile composite soil nailing support system is summarized, and the stress mechanism of the whole support system is comprehensive analyzed, and some corresponding calculation method is introduced concisely.3) Contrasting with the existing methods, some theory research methods in stirring pile composite soil nailing support system are introduced and summarized, the applicability, advantages and disadvantages of these methods are concluded in detail. According to the numerical analysis method and the limit equilibrium method commonly used in the Chinese engineering design work, similarities and differences are analyzed, extensive geotechnical numerical simulation research should be conducted extensively, in order to match the design software design and to get better economic and environmental benefits.4) Set grain filling soil excavation support as an example, based on the displacement deformation theory research about the existing foundation pit supporting system, FLAC3D finite difference software is used to establish a three-dimensional numerical constitutive model of the cement-soil pile composite soil nailing support structure system. Through the further analysis, in order to realize the function mechanism of excavation pit slope deformation, the paper reveal that numerical simulation analysis can accurately predict and simulation the slope deformation, thus the excavation engineering comparison of structural design and optimization in the design experience are related. Finally, some references for the design opinion are provided.