Study On Longitudinal Vibration Of Transversely Isotropic Soil-large Diameter Pile

The study of pile-soil dynamic characteristics has always been an important issue in the field of pile foundation engineering.In this paper,the longitudinal vibration of large-diameter piles in transversely isotropic soil under longitudinal vibration load is studied,and the dynamic response of pile-soil parameters to pile-soil is analyzed.Finally,the finite element software is used to verify the obtained theoretical solution.The main research contents are as follows:(1)Based on the constitutive equation of the transversely isotropic material,the motion equation of the soil under axisymmetric conditions is established,and the large-diameter pile is regarded as the Rayleigh-Love rod considering the transverse inertia force,and the dynamic equation of the pile-soil system is established,combined with the boundary conditions and initial conditions,the dynamic equation is solved mathematically,and the dynamic response solution of the pile top is obtained.On the basis of the obtained pile displacement solution,the analytical solution of soil displacement is reversed to obtain the expression of the complex shear stiffness of the soil at the contact surface of the pile and soil.The influence of pile-soil dynamic response;(2)Considering factors such as the layering of the soil and the defects of the pile body,the pile-soil model is longitudinally layered,and the soil layers are connected by distributed Voigt elements.The analytical solution of the dynamic response of the pile top is obtained by the recursive method.On this basis,the effects of transverse isotropic parameters,shrinking(expanding)necks,and variable section positions on the dynamic response of the pile top are analyzed;(3)Combined with the theory of porous media,the longitudinal vibration equation of the large-diameter pile in the transversely isotropic saturated soil is established,and the solution is solved,and the analytical solution of the dynamic response of the top of the large-diameter pile is obtained.The influence of parameters such as volume fraction on the dynamic response of piles and soils and the comparison between saturated soils and dry soils;(4)The vibration model of large-diameter piles in transversely isotropic soil was established by ANSYS finite element software,and different transversely isotropic parameters,different pile diameters,different supporting conditions,shrinking(expanding)necks,and saturated soil were analyzed.The dynamic response of the lower pile-soil system is compared with the theoretical solution to verify the correctness of the theoretical solution in this paper.