Numerical Simulation Of Multi-Layer Soil-Pile-Structure Nonlinear Seismic Response And Pile Foundation Design

Strong earthquake observation shows that the pile foundation has good seismic performance,most of the pile foundation can withstand a certain degree of seismic impact,but there will also be seismic damage of pile foundation,so it is necessary to carry out seismic design of pile foundation.However,the conventional seismic analysis method is to consider the superstructure,pile and soil separately.For the soft soil foundation,this analysis method is unreasonable.The reasonable method should consider the soil pile structure interaction.In this paper,the 32 m double track simply supported beam gravity pile foundation pier of high-speed railway is taken as the engineering background,the Winkler foundation beam theory is taken as the foundation,the soil spring parameters are solved based on p-y curve method,the multi-layer soil pile structure interaction nonlinear numerical model is established by Midas civil finite element software,and the seismic response analysis and pile foundation design are compared.The main work is as follows:(1)This paper summarizes the development of soil pile structure interaction at home and abroad,and focuses on the calculation points of lumped mass model and Winkler foundation beam model.(2)The calculation method of spring parameters of Winkler foundation beam is summarized.Based on the p-y curve method,the resistance displacement curve of soil spring is calculated.In order to simplify the calculation,the conversion formula of p-y curve equivalent to double broken line is derived.The influence of cohesion,internal friction angle,compression coefficient,bulk density and pile diameter on the mechanical behavior of single pile is explored.(3)This paper introduces the mechanical model of structure and soil,and discusses the mechanism of pile pile soil pile mechanical model.(4)The selection of seismic wave,the solving process of Mander constitutive model of circular end section confined concrete,the establishment of restoring force model of pier and pile foundation,the calculation of structural damping and soil damping parameters,the calculation of seismic mass,the addition of dead load and the establishment of the model are introduced in detail.The model can comprehensively consider the structural nonlinearity,soil nonlinearity,pile-soil contact nonlinearity,soil between piles and soil between piles The deformation and stress characteristics of pile group foundation,yield process and yield state of pier body,hysteretic curve of pier body,energy dissipation characteristics of structure,hysteretic curve and stress state of soil spring are studied.(5)On the basis of the fourth chapter model,the parametric analysis of soil pile structure interaction is carried out,and the influences of the springs between piles,the horizontal springs on the side of pile cap,the position of soft soil layer,the thickness of soft soil layer and the hardness of the first layer of soil on the response of pier body and pile body are analyzed.(6)The influence of simplified analysis method and interaction analysis method on reinforcement of pile foundation is compared.