软弱层几何特性与剪切波速对场地反应谱的影响研究

发布时间：2018-01-16 08:28

  本文关键词：软弱层几何特性与剪切波速对场地反应谱的影响研究　出处：《防灾减灾工程学报》2016年05期 　论文类型：期刊论文

  更多相关文章： 反应谱 软弱土层 场地效应 真非线性地震反应分析 土的滞回模型 非线性动力特性

【摘要】：场地土层结构对地震动的影响一直备受关注。针对含有一层软弱土层的匀质场地展开非线性地震反应分析,研究了软弱土层的几何分布特性和剪切波速变化对地表反应谱的影响。结果表明:1软弱层使得场地反应谱特征周期延长,长周期段曲线升高并出现多峰值现象,含软弱层场地的反应谱与无软弱层场地的反应谱差值比远大于工程可接受的误差范围。2软弱层所引起的最大反应谱差值比随软弱层厚度和埋深的增加而近似线性增大,随软弱层剪切波速的减小而非线性增加,在本文算例中,最大反应谱差值比接近12倍。3反应谱最大差值比所对应的敏感周期随着软弱层厚度、埋深和输入加速度幅值的增加而增大,随剪切波速的减小而增大。分析表明,软弱层中的剪应变远大于邻近正常土层中的剪应变,这是引起地表加速度反应谱发生改变的主要原因。
[Abstract]:The influence of site soil structure on ground motion has been paid much attention. Nonlinear seismic response analysis is carried out for homogeneous site with a layer of soft soil. The effects of the geometric distribution of soft soil layer and the variation of shear wave velocity on the surface response spectrum are studied. The results show that the weak layer of 1 / 1 makes the characteristic period of the site response spectrum longer. The long-period curve increased and appeared the phenomenon of multi-peak value. The ratio of response spectrum difference between site with weak layer and site without weak layer is much larger than that of engineering acceptable error range .2 the ratio of maximum response spectrum difference caused by weak layer increases with the increase of thickness and buried depth of weak layer. Sex increases. With the decrease of shear wave velocity in the weak layer, the nonlinear increases. In this example, the sensitivity period of the maximum response spectrum difference ratio is nearly 12 times that of the maximum response spectrum difference ratio with the thickness of the weak layer. The increase of buried depth and the amplitude of input acceleration increases with the decrease of shear wave velocity. The analysis shows that the shear strain in the weak layer is much larger than that in the adjacent normal soil layer. This is the main reason for the change of surface acceleration response spectrum.
【作者单位】： 湖南工业大学土木工程学院;香港大学土木工程系;
【分类号】：TU435;P315.9
【正文快照】： 引言软弱层作为局部场地条件中的一种特殊情况,其对场地地震动的影响一直是地震工程领域重点关注的问题[1-7]。我国现行规范对场地条件的考虑仅基于等效剪切波速和覆盖层厚度划分场地类别,对于场地中存在的软弱层不能敏感地反映,可能使地震动参数取值偏低,造成建(构)筑物的安，

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