Study On Longitudinal Vibration Of Complex Layered Soil-pipe Pile

Pipe piles are widely used,and theoretical research has been continuously strengthened.However,current researches consider the pile side as a single-phase or saturated single soil,ignoring the complex stratification of the soil itself.This paper takes the groundwater level as the boundary.Considering that the side of the pile is single-phase-saturated complex layered soil,the dynamic response of the pile top when supporting different pile bottoms and when there is soil plugging effect is analyzed.Mainly through two major aspects of theoretical analysis and numerical verification,the specific content is divided into four points:(1)Considering that the bottom of the pile is supported by viscoelasticity,establish coupling vibration models of single-phase soil and saturated soil and pipe piles,and then solve the pile-soil dynamic equations to analyze groundwater level,pipe pile wall thickness,and single-phase soil shear The influence of the change of shear wave velocity on the dynamic response of the pile top,and the influence of layered single-phase soil,singlephase-saturated complex layered soil,and layered saturated soil on the side of the pile are compared.The study found that the nature of the pile side soil has the most significant influence on the dynamic curve of the pile top.(2)Consider the effect of soil plugging when the pile bottom is supported by viscoelasticity.According to the pile-soil model,the shear complex stiffness of the outer and inner sides of the pipe pile is obtained,and the impedance of the top of the pile is obtained according to the impedance transferability,and then the expressions of velocity and displacement are obtained.The soil plug density,wave velocity,height,and water volume are analyzed.The effect of score changes on the dynamic response of the pile top.The study found that: soil plugging is an aspect that cannot be ignored in the study of pipe piles.(3)Considering that the bottom of the pile is supported by virtual soil piles,the coupling vibration models of single-phase soil and saturated soil and pipe piles are established respectively,and then the pile-soil dynamic equation is solved,and the effects of soil thickness,longitudinal wave velocity and density change on the pile tip are analyzed.The influence of the dynamic response of the pile top,and the existence of soft and hard interlayers in the complex layered soil on the side of the pile are also studied.The study found that the influence of the thickness of the soil layer at the end of the pile and the soft and hard interlayer on the side of the pile is obvious.(4)Use ANSYS finite element software to establish a model with viscoelastic support for pile bottom,virtual soil pile support,and a model considering soil plugging effect,perform numerical calculations on the relevant parameters under each type of model,and extract data for a certain node on the top of the pile.The velocity time domain curve is compared with the corresponding theoretical curve to confirm that the theoretical solution is correct.