Numerical Simulation And Application Research On The Performance Of Pile Net Composite Foundation With High Fill Embankment

Pile-net composite foundation has the characteristics of horizontal and vertical reinforced composition foundation,which shows the unique advantage on strengthening soft soil foundation.However,as the complicated working mechanism of Pile-net composite foundation,the theoretical research lags behind the engineering practice obviously,design philosophy and calculation method have not been formed perfectly.Based on the high embankment of soft ground project on Shangqiu to Hangzhou high-speed railway engineering.Systematic numerical simulation analysis and field monitoring have been used to the research on the characteristics of Pile-net composite foundation at high-filled embankment.The main work and achievements are as following:(1)The systematic numerical simulation of deformation and force characteristics of the pile-reinforced foundation with the given parameters was carried out,Which aimed to roadbed deformation and pile mechanical behavior.The study showed that during the preloading period of the subgrade,the preloading time of 6 months is the critical value of the increase of subgrade settlement,and thereafter the settlement of subgrade is changed little.The axial force change of pile body is "small at both ends and big in middle",and the axial force varies little with time.(2)Based on the numerical analysis of the deformation and force characteristics,factors that influence the characteristic parameters of pile-net composite foundation is studied and determines the high embankment performance optimization of the distance between piles,the size of pile cap and stiffness.(3)The MIDAS GTS numerical analysis software was used to establish the model of the three-dimensional pile-net composite foundation under embankment load,which consider the pile-soil friction contact and Various conditions.Pile-net composite foundation are analyzed in detail the mechanical properties and deformation characteristics of forming process;The influence of different pile spacing,pile cap size and pile modulus on the deformation and stress characteristics of the pile foundation in the pile-net composite foundation is discussed.(4)According to the numerical simulation analysis,the parameters of pile foundation composite foundation in Chaohu section of Shangqiu to Hangzhou high-speed railway are recommended,and that are applied to guide the design and construction of the project.The result of field monitoring and analysis shows that the calculated results are agreement with the measured results,which proves the rationality and feasibility of the proposed scheme in this paper.