饱和地基轴对称竖向振动有限元-无限元耦合解

Hybrid Finite-Infinite Element Method for Axis-Symmetrically Vertical Vibrations of Saturated Media

根据饱和土弹性波动方程和波的传播特性,建立了饱和地基轴对称竖向振动问题的一种有限元-无限元耦合解法并编制了计算程序;对可蜕化为单相弹性地基的气饱和土(干土)与渗透性很差的水饱和土地基,应用该方法计算了Lamb问题的地表竖向位移,其结果与既有单相弹性地基的理论解吻合良好.所提出方法可为求解层状饱和地基轴对称动力问题、研究饱和土中单桩复合地基动测技术等提供一种较为简便而可靠的分析手段.

Based on the dynamic governing equations of elastic waves, a hybrid finite-infinite element method was proposed for analyzing axis-symmetrically vertical vibrations of saturated media. The finite element is to model the near-field solution and the infinite element is used to represent the soil which extends to infinity. The decay functions of the infinite element were derived based on the propagation of waves in saturated media in great details. Using the compiled program, the surface vertical displacements of the air-saturated ground (dry soil) and of the water-saturated stratum with extremely low permeability were calculated under a surface point excitation (called Lamb's problem), which leads to the results agreed very well with the existing theoretical solutions of single-phased elastic media. The proposed method is a simple and reliable numerical method, which has good accuracy and gives large savings in time and expense and can be used to solve the axis-symmetrically dynamic problems of layered saturated media and to get the mechanism of dynamic testing on single-piled composite saturated foundation.