桩-土-结构动力相互作用影响因素分析

Analysis of dynamic interaction influence factors of pile-soil-structure

为了研究桩-土-结构动力相互作用机理,分析其影响因素,采用振动台试验和数值模拟分析相结合的方法,对不同上部结构质量、不同输入波频率和加速度峰值输入下的桩-土-结构体系的水平动力反应规律进行了分析和讨论。试验地基土体模型为中硬土,剪切波速约为213 m/s;群桩基础由5根长1.35 m、直径0.1 m的基桩“十”字型布置;上部结构模型采用质量块模拟。研究结果表明:桩身的弯矩与剪力在桩-承台连接处最大,并且随深度增加而减小;随着上部结构质量的增加,土体与桩基的加速度反应增大,桩身的弯矩与剪力也增大;随着输入正弦波幅值和频率的增大,桩-土运动相互作用变大,桩身弯矩与剪力变大;最后比较各种影响因素引起的反应发现,上部结构质量的变化对桩-土-结构体系动力相互作用的影响最大,幅值的影响次之,频率的影响最小。

In order to study the mechanism of pile-soil-structure dynamic interaction and analyze its influencing factors,the horizontal dynamic response laws of pile-soil-structure system under different superstructure mass,different input wave frequency and acceleration peak input are analyzed and discussed by using the method of shaking table test and numerical simulation analysis.The soil model of the test foundation is medium hard soil,and the shear speed is about 213 m/s.The pile group foundation is composed of five foundation piles with a length of 1.35 m and a diameter of 0.1 m arranged in cross shape.The superstructure model is simulated by mass block.The experimental results show that the bending moment and shear force of pile body are the largest at the pile-bearing joint,and decrease with increasing depth.With the increase of the superstructure mass,the acceleration reaction between soil and pile foundation increases significantly,and the bending moment and shear force of the pile body also show an increasing trend.With the increase of the input sine wave amplitude and frequency,the motion interaction becomes larger,and the bending moment and shear force in the pile body become larger.The change of superstructure quality has the greatest impact on the dynamic interaction of the pile-soil-structure system,followed by amplitude and frequency.