饱和柔性桩复合地基表面振动特性研究

项目名称： 饱和柔性桩复合地基表面振动特性研究

项目编号： No.51208297

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 建筑环境与结构工程学科

项目作者： 宋春雨

作者单位： 上海交通大学

项目金额： 25万元

中文摘要： 表面波技术一直试图被工程界用来检测竖向柔性桩复合地基的质量，但饱和土体中的流固耦合效应及竖向柔性桩对波动信号的干扰使该问题变得异常复杂。本项目针对饱和土中柔性桩复合地基，拟建立饱和介质三维动力有限元无限元耦合模型，分析地面点源激振作用下饱和柔性桩复合地基振动场，考察桩土渗透系数、柔性桩体的反射、透射和绕射作用以及柔性桩之间的相互干扰对表面振动信号的影响。研究地面振动信号的幅频、相频特性随振源和柔性桩空间位置变化而变化的规律。论证目前复合地基设计中套用水平层状地基等效计算方法的局限性。现场对水泥搅拌桩、砂石桩复合地基进行多道表面波试验，验证柔性桩的物理几何特性及空间布置形式在表面波频散曲线上的反应特征。并应用饱和介质有限元无限元耦合解分析桩土参数对实测信号的灵敏度，在此基础上，反演复合地基的工程参数。本项目研究成果将使表面波法测试复合地基的结果更加可靠，同时进一步完善复合地基表面振动传播理论

中文关键词： 复合地基；表面波；振动导纳；饱和介质；有限元无限元

英文摘要： Surface wave has been used to investigate the composite foudation with cement mixing piles or gravel colunms.The fluid-soid coupling in saturated media and vertical cement mixing piles and gravel colunms will effect on the signal of the surface wave. The disturbance signals make the analysis of surface wave signal become more difficult. In this proposal,the formulations of 3D infinite elements for dynamic analysis of vibration problems in saturated composite foundation will be derived. Using the proposed finite-infinite element method, the vibration response of saturated composite foundation will be calculated to study the influences of the permeabilities of soil on the surface wave signals. At the same time, the surface wave scattering by cement mixing piles or gravel colounms was analyzed. The influences of pile-pile interaction on surface wave signal will be investigated. The regulations of amplitude and phase to frequency of surface wave in the composite foundation will be summarized to verify the limitation of equivalent method based on the theories of surface wave in stratified medias which has been used to investigate composite foundation. In the field of composite foundation, the surface wave tests will be performed to pursue the properties of surface wave dispersion curve. The influence of the pile s

英文关键词： composite foundation；surface wave；mechanical admittance；saturated media；finite-infinite element