深厚软土场地中三维凹陷地形非线性地震响应分析

发布时间：2018-04-04 06:44

本文选题：三维凹陷地形　切入点：地震响应　出处：《岩土工程学报》2017年07期

【摘要】：采用黏弹性人工边界并结合地震动输入等效结点力法实现半无限场地的波动输入,采用等效线性法模拟土体的非线性特征,基于有限元软件ABAQUS,建立弹性基岩上覆深厚软土中三维凹陷地形非线性地震响应分析模型。通过与文献比较,验证了整体模型的精度。以天津地区某一浅椭球凹陷地形为例进行数值计算,比较了非线性地震响应与线性地震响应的差别,并进一步分析了三维凹陷地形对非线性地震响应造成的影响,最后计算了在地震安全性评价人工波作用下三维凹陷地形的非线性地震响应。研究表明,土体的非线性特征对三维凹陷地形地震响应有显著影响。研究还发现一个特殊现象,即凹陷地形中心附近的非线性地震响应可能会大于其线性地震响应,且地震激励幅值越大,这一现象越明显。对于三维复杂局部场地的非线性地震响应研究,模型具有一定的参考价值。
[Abstract]:Using the viscoelastic artificial boundary and the equivalent node force method of ground motion input, the wave input of semi-infinite site is realized, and the nonlinear characteristics of soil are simulated by the equivalent linear method.Based on the finite element software Abaqus, the nonlinear seismic response model of 3D depression in deep soft soil overlying elastic bedrock is established.The accuracy of the whole model is verified by comparing with the literature.Taking the topography of a shallow ellipsoidal sag in Tianjin as an example, the difference between nonlinear seismic response and linear seismic response is compared, and the influence of 3D depression topography on nonlinear seismic response is further analyzed.Finally, the nonlinear seismic response of 3D depression terrain under the action of artificial wave is calculated.The results show that the nonlinear characteristics of soil have a significant effect on the seismic response of 3D sag.It is also found that a special phenomenon is that the nonlinear seismic response near the center of the depression may be larger than its linear seismic response, and the larger the amplitude of the seismic excitation, the more obvious this phenomenon is.The model has some reference value for the study of nonlinear seismic response of 3D complex local site.
【作者单位】：天津大学水利工程仿真与安全国家重点实验室;天津大学建筑工程学院土木工程系;
【基金】：国家自然科学基金项目(51578372)
【分类号】：TU435

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