中文摘要：

通过解析方法研究了横观各向同性饱和土体中弹性桩的扭转振动响应问题．土体和弹性桩体系被分解为横观各向同性饱和土及被视作土体加强体的虚拟桩部分，土体符合Blot三维饱和弹性介质理论，弹性桩被视为一维弹性长杆．运用Hankel变换求解了横观各向同性饱和土体的动力控制方程，结合桩土间复合边界条件，得到关于桩身内力沿桩长分布的第二类Fredholm积分方程．利用数值的方法对方程进行求解，得出应力沿桩身的分布，并可进一步得到桩的位移沿深度的分布．数值计算表明，土体的横观各向同性参数及荷载频率对弹性桩的振动影响显著．

英文摘要：

An analytical method was presented for analysis of the torsional vibration of an elastic pile embedded in transversely isotropic saturated soil. The bar-porous medium system was decomposed into an extended transversely isotropic porous medium system and a fictitious pile as a reinforcement. The soil was governed by Blot＇s three-dimensional elastodynamic theory, and the pile was modeled by one-dimensional elastic theory. Hankel transform was used to solve the dynamic governing differential equations of the saturated poroelastic soil. Considering the mixed boundary-value conditions at the interface of pile and soil; a Fredholm;s integral equation of the second kind for the bar-force was established. The bar-force was determined by numerical method; and then the angle of twist of pile. The numerical calculation indicates that the characters of soil and load frequency affect the vibration obviously.