Study on dynamic response of pile foundation in transversely isotropic soil under the action of SH harmonic seismic wave

First， using one-dimensional wave theory， the horizontal displacement of transversely anisotropic soil layers under vertical incidence of SH harmonic seismic waves was obtained. Next， the dynamic interaction between transversely isotropic soil and pile was described using the Winkler spring-damper model. The stiffness and damping coefficients of the Winkler spring-damper were obtained by solving the horizontal vibration of transversely isotropic soil in axisymmetric coordinates. Then， the horizontal vibration of pile in transversely isotropic soil was solved by considering the influence of horizontal displacement generated by SH harmonic seismic wave， and the amplification factor at the top of the pile foundation was obtained. Finally， the influence of relevant parameters on the dynamic response of pile in transversely isotropic soil under SH harmonic seismic wave was analyzed through numerical examples. The research results indicated that， under the action of SH harmonic seismic wave， the transversely isotropic soil-pile system exhibited a steady-state response. The first peak of the curves of amplification factor at the pile top varying with dimensionless frequency corresponded to a relatively fixed frequency， while the size and position of the second peak were influenced by the parameters of pile and soil. The shear modulus ratio G_hv on the horizontal and vertical planes of isotropic soil mainly affected the size of the second peak. The pile-soil modulus ratio E_p/G_hv， pile-soil density ratio ρ_p/ρ， and pile diameter-length ratio r₀/H had a significant impact on this peak.