不均匀饱和土中变波阻抗桩的纵向振动特性  

Longitudinal vibration characteristics of piles with variable wave impedance in inhomogeneous saturated soils

作　　者：高放 刘东甲[1] 常新敏[1] 卢志堂[1] GAO Fang;LIU Dongjia;CHANG Xinmin;LU Zhitang(School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《合肥工业大学学报（自然科学版）》2019年第2期247-251,共5页Journal of Hefei University of Technology：Natural Science

基　　金：中央高校基本科研业务费专项资金资助项目(JZ2016HGBZ1028);安徽省高速公路控股集团有限公司资助项目(AHGS2013-3);安徽省城建设计研究总院有限公司资助项目(W2016JSKF0446)

摘　　要：为揭示饱和土中桩的纵向振动特性,文章建立了不均匀饱和土中变波阻抗桩的纵向振动模型。利用Laplace变换,得到了土层平面应变模型下对桩身的动力阻抗,并求得了桩身任意段的动力响应;利用传递矩阵,给出了桩顶复刚度的解析表达式;阐明了单相土模型的不足,并分析了桩身缺陷及饱和土渗透性对桩动力特性的影响。结果表明:采用单相土模型会低估桩顶低频段的动刚度,对动阻尼影响较小,一定程度上说明了土体模型对分析桩动力特性的重要性;桩身存在缺陷会使桩顶的动刚度明显减小,动阻尼增大;饱和土渗透性变差会有效增大缺陷桩的动刚度,减小桩的共振频率,并减缓动阻尼随频率变化的增长速率。In order to reveal the longitudinal vibration characteristics of piles in saturated soils,the longitudinal vibration model of piles with variable wave impedance in inhomogeneous saturated soils is established.Using the Laplace transform,the dynamic impedance of the pile is obtained with the plane strain model of soils and the dynamic response of the pile is obtained.The analytical expression of the complex stiffness of the pile top is presented by using the transfer matrix.The deficiency of the single-phase model of soil is described, and the influence of the defects of the pile and the permeability of saturated soil on the dynamic characteristics of the pile is analyzed. The results show that if the single-phase model of soil is applied,the dynamic stiffness of the pile top in the low frequency section will be underestimated,while the dynamic damping changes a little,which shows the importance of the soil model to analyze the dynamic characteristics of the pile to some extent;the dynamic stiffness of defective pile can be reduced significantly,but its damping increases;with the decrease of the permeability of saturated soil,the dynamic stiffness of the defective pile becomes large,but the resonance frequency of the pile and the growth rate of dynamic damping with frequency decrease.

关 键 词：不均匀饱和土 变波阻抗 桩 纵向振动 动力特性 

分 类 号：TU473.16[建筑科学—结构工程]