饱和土径向运动简化的桩纵向振动特性研究  

Study on Dynamic Response of Pile Vertical Vibration in Saturated Soil Considering Simlified Radial Motions

作　　者：李强[1] 王奎华[2] 

机构地区：[1]浙江海洋学院土木工程系,浙江舟山316004 [2]浙江大学建工学院岩土工程研究所,浙江杭州310027

出　　处：《应用基础与工程科学学报》2008年第3期446-456,共11页Journal of Basic Science and Engineering

基　　金：国家自然科学基金(50279047);浙江省教育厅2005年度科研计划项目(20050111);浙江海洋学院博士基金项目(210450066);浙江省科技厅优先主题项目(2007C13065)

摘　　要：在三维轴对称饱和土层中弹性支承桩纵向振动研究的基础上,通过简化饱和介质中固相与液相径向运动,建立了饱和土中桩纵向振动的简化模型,通过分离变量法求得了简化模型的桩纵向振动的频域解析解,利用付立叶逆变换和卷积定律获得了时域半解析解.简化解与三维轴对称饱和两相解的桩顶动力响应的对比结果表明,在低频范围内简化解的动刚度因子及等效阻尼与三维轴对称解有较大差别,而较高频率范围内两种解的导纳和速度时域响应基本吻合,因此简化理论对基桩频域或时域检测是足够精确的.计算结果表明,桩的长径比、桩土模量比以及桩底支承系数对桩顶频域和时域响应影响显著,而渗透系数对桩顶动力响应的影响较小.Based on solutions of pile vertical vibration in saturated soil under three dimensional axisymmetric model, a simplified dynamic model of soil-pile interaction was presented by simplifying the radial motions of solid phase and liquid phase of saturated soil. Analytical solutions in frequency domain were derived using the seperation of variable method. Then semianalytical solutions in time domain were obtained by means of Fourier inverse transform and convolution operation. By comparison the present solutions with the ones considering the radial motions, the results showed that there were obvious differences of dynamic stiffness factor and equivalent damping at the lower frequency. However at the higher frequency, the admittance and velocity at pile head of the two solutions were in good agreement. Such a conclusion could be conducted that the present model was precise enough to apply to pile dynamic test. Numerical results showed that there were three major factors on pile dynamic response, i. e. the pile slenderness, the modulus＇ ratio of pile and soil and coefficient of bearing reaction of pile. And the effect of the permeability of soil on pile dynamic response was minor.

关 键 词：饱和土 弹性支承桩 纵向振动 动力响应 

分 类 号：TU473.12[建筑科学—结构工程]