Application And Optimization Of CFG Pile Composite Foundation In Liunan Expressway Soft Foundation Treatment

The foundation is the most basic condition of the expressway construction.The repeated load will lead to the decrease in the bearing capacity of the foundation and the increase in the settlement deformation of the foundation.In order to ensure the safety use of the expressway,the strength and stiffness of the foundation must meet some requirements.Hence,more and more attentions are paid to the soft foundation treatment in expressway.Due to advantages of low cost,short construction period and good reinforcement effects,CFG pile composite foundation is widely used under construction.With a variety of design methods putting forward and more and more practice conducting in CFG pile composite foundation there is a rapid development in the theory and practice of composite foundation.Based on the existing research results of CFG pile composite foundation,this essay systematically analyzes the bearing characteristics and mechanism of CFG pile composite foundation.First,the prediction and summary of differential settlement of CFG pile composite foundation on soft foundation of reconstruction and extension of Liunan expressway bridge head lay the foundation for the soft foundation CFG pile treatment scheme optimization of bridge head sections,which rely on construction and establish the finite element numerical simulation model.Secondly,relying on the relevant information of the soft foundation treatment project of the bridge south of the Liunan expressway,a variety of design methods and engineering application are studied comprehensively.Depending on systematical analyses of CFG pile treatment scheme in the soft foundation section of reconstruction and extension of Liunan expressway,the regularity of settlement in the direction of cross section of subgrade,and the calculation and analysis of the bearing capacity of cement fly ash gravel pile composite foundation under different pile spaces,the arrangement of cement fly ash gravel pile spacing and pile length is made.Last,according to the results of theoretical analysis,the CFG treatment scheme in soft foundation section of reconstruction and extension of Liunan expressway is rationally evaluated and the scheme of layout of CFG pile and the setting of pile length is optimized.According to the optimization scheme of reconstruction and extension of Liunan expressway,this essay will analyze the efficiency and rationality of CFG pile space and the change of pile length.