Analysis Of Pile-soil Dynamic Interaction Based On Pasternak Foundation Model

With the rapid development of society,more and more industrial buildings and civil buildings are rising,and the application of pile foundation becomes more common,which puts forward higher requirements for pile foundation design.Through the contact between side and soil,the pile foundation transfers the upper load to the soil around the pile body,or to the deeper rock and soil,so as to obtain a strong bearing capacity to ensure the safety of the building.Therefore,the pile-soil interaction has become a problem that must be considered when designing the pile foundation.Pilesoil interaction analysis mainly includes single pile-soil interaction analysis and pile group-soil interaction analysis.This paper is based on Pasternak foundation model.The transfer matrix method is used to consider the layered characteristics of foundation soil.The characteristics of pile-soil interaction will be further discussed,focusing on the dynamic interaction characteristics of pile-soil interaction in layered foundation under horizontal harmonic load.Through theoretical analysis,the interaction mechanism between single-pile group and soil will be understood,which will provide reference for practical engineering design.The main contents of this paper are divided into five chapters,which are as follows:(1)By summarizing a large number of related literatures,this paper describes the significance of the research on pile-soil interaction,gives the current situation and analysis methods of soil-structure interaction at home and abroad,summarizes the research methods and prospects of pile-soil interaction,and puts forward the main contents and ideas of this paper.(2)The Pasternak foundation beam is analyzed,and the elastic element and viscous element are effectively combined,that is,the stiffness of the foundation can be considered and the consumption caused by the stress wave propagation can be well simulated.The differential equation of motion of Euler beam on viscoelastic Pasternak foundation is established.Considering the stratification of natural soil,the stratified foundation is analyzed.(3)Considering the shear capacity of foundation soil in Winkler foundation model,The dynamic interaction factor of adjacent pile is obtained by using transfer matrix method,and the impedance of pile group is further deduced.The horizontal dynamic interaction of single-pile group under axial force is studied.The influence of pile top axial force on the horizontal dynamic effect of pile groups is expounded in a relatively concise way.The simplified method for solving the dynamic impedance function of single pile-pile groups in layered soil foundation is extended.The validity of the model is verified by comparison with related examples.(4)Analyse the influence of soil compression modulus,soil shear effect,pile top axial force,pile bottom boundary conditions on the impedance of single pile,and analyze the influence of soil properties,pile top axial force,pile spacing-diameter ratio,excitation frequency,pile length diameter ratio and pile angle on adjacent pile interaction factors and pile group impedance.(5)The internal force and displacement of pile body based on Pasternak foundation model are studied.The internal force of single pile in pile group is calculated by superposition method which is consistent with the displacement of pile group.The internal force of pile body is equal to the sum of the internal force caused by the load on the top of pile itself and the additional internal force caused by the vibration of adjacent pile.The effects of shear stiffness,axial force at pile top,elastic modulus ratio of pile to soil and ratio of pile spacing to diameter on displacement of pile body or internal force of pile body are studied.