桩-承台竖向强迫振动试验和分析  

Vertical Dynamic Test and Analysis of Pile-pile Cap

作　　者：陈镕[1] 蒋振华[1] 薛松涛[1] 王远功[1] 

机构地区：[1]同济大学结构与防灾研究所,上海200092

出　　处：《同济大学学报（自然科学版）》2004年第7期846-850,共5页Journal of Tongji University:Natural Science

基　　金：国家杰出青年科学基金资助项目 ( 5 992 5 82 0 )

摘　　要：采用横观各向同性 (TI)层状弹性模型来模拟半空间上的层状场地 ,计算中忽略土体水平位移对竖向位移的影响 .用常系数阻尼器代替半空间 ,以吸收上部场地传至下边界的振动能量 .利用薄层元素法和子结构法建立运动方程 .在推导过程中 ,先利用格林公式算得自由场地刚度矩阵 ,再与桩单元刚度矩阵拼装得到桩的竖向总刚度矩阵 ,在此基础上推出单桩 -承台及双桩 -承台体系在垂直简谐荷载作用下的阻抗函数 ,其中双桩的阻抗函数考虑了桩 -土 -桩的动力相互作用的影响 .利用牛顿第二定律推导出这 2种体系在竖向强迫振动下的响应公式 .利用某次桩基动力试验所得的土参数和激振器数据 ,分别计算出这 2种体系的第一共振频率及频响曲线 ,并将计算结果与试验结果进行比较 .The transversely isotropic elastic strata are used to simulate the layered ground above the half space.The effect of horizontal displacement of the soil on the vertical displacement is neglected in calculation.The half space is replaced by dampers with constant coefficients,which are used to absorb the vibration energy transmitted into the half space.The motion equations can be derived by using the methods of the thin layer and substructure.During the process,the Green's functions are used to obtain the stiffness matrix of the free ground.The total vertical stiffness matrix of the pile can be obtained through joining the stiffness matrix of single pile and the matrix of the free ground.Based on these stiffness matrixes,the impedance functions of the systems of the single piles and the doubles pile can be deduced when they are excited by vertical harmonic forces.The effect of pile-soil-pile interaction is considered in deducing the impedance function of the double pile.Then the response formulas of the two systems under the harmonic forces can be derived by using Newton's second law.Using these formulas and all test parameters from one dynamical test,the frequency response functions of these two systems are evaluated.Finally,the calculation results and the test results are compared.

关 键 词：桩-承台 横观各向同性 阻尼边界 阻尼界 阻抗函数 激振器 

分 类 号：TU435[建筑科学—岩土工程]