双层饱和弹性土中埋置弹性桩的扭转振动

为研究双层饱和地基中埋置弹性圆桩的扭转振动响应.考虑低频荷载下弹性桩符合一维弹性模型,而饱和土体符合Biot三维饱和弹性介质理论.基于虚拟桩模型,桩-土体系被离散为一连续的饱和半空间双层地基及一虚拟桩模型.土体的控制方程在Hankel变换域内进行求解.虚拟桩的动力方程结合桩土间应力及位移协调条件,得到关于虚拟桩内力的第二类Fredholm积分方程,离散积分方程求解得到虚拟桩内力的数值解.通过进一步计算可得到原弹性桩的内力及位移.数值计算部分考虑了土体各参数对于问题的影响.

Torsional vibration of elastic pile embedded in a two-layer poroelastic medium

The dynamic response of a cylindrical elastic pile embedded in a two-layer poroelastic medium and subjected to torsional loading was considered. The pile was modeled with 1D elastic theory at low frequencies,and the poroelastic medium employed Biot’s three-dimendional elastodynamic theory. Based on the fictitious pile schemes,the pile-porous medium system was decomposed into a fictitious pile system and a two-layer poroelastic medium system. The governing equations for Biot’s theory were resolved through the application of Hankel transform. 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 inner force and the displacement of the pile were calculated by applying numerical quadrature. The influences of the upper layer thickness and the frequency were studied.