不同地层波速模型对沉积谷地地震响应规律的影响：FEM-IBIEM模拟研究

刘中宪; 王冬

doi:10.11779/CJGE201407013

不同地层波速模型对沉积谷地地震响应规律的影响：FEM-IBIEM模拟研究 English Version

刘中宪^{1, 2, 3},
王冬^{1, 2}

1. 天津城建大学,天津 300384; 2. 天津市软土特性与工程环境重点实验室,天津 300384; 3. 天津市地震工程研究所,天津 300384

基金项目: 国家自然科学基金项目（51278327）; 国家重点基础研究发展计划（973计划）(2011CB013603); 天津市应用基础与前沿技术研究项目（14JCYBJC21900）

详细信息

作者简介:
刘中宪(1982- ),男,河南泌阳人,博士后,副教授,主要从事地震工程、工程波动领域的研究和教学工作。E-mail: zhongxian1212@163.com。

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出版历程
- 收稿日期: 2013-07-04
- 发布日期: 2014-07-24

Effect of different wave velocity models on seismic response of alluvial valley based on FEM-IBIEM

LIU Zhong-xian^{1, 2, 3},
WANG Dong^{1, 2}

1. Tianjin Chengjian University, Tianjin 300384, China; 2. Key Laboratory of Soft Soils and Engineering Environment of Tianjin, Tianjin 300384, China; 3. Earthquake Engineering Research Institute of Tianjin City, Tianjin 300384, China

摘要

摘要: 准确的地层波速模型是场地反应分析的关键,而实际地层波速测定存在很大的不确定性。计算中通常采用简化的均质和分层模型,或者根据钻孔数据将波速沿深度进行线性、二次或指数拟合。这些不同波速模型对沉积谷地地震响应的影响规律究竟如何目前尚未得以厘清。为此尝试采用有限元—间接边界积分方程耦合方法,通过频时域定量计算,从波动学角度揭示不同波速模型沉积谷地地震响应的差别及其本质所在。数值计算结果表明：低频波入射时(),常用的几种波速模型对地表位移反应影响不大。但随着频率增大,不同波速模型对计算结果的影响不能忽略。着重考察了线性模型和均质模型之间的反应差别：发现线性模型情况下高频共振和盆地边缘效应更为显著,由此导致地震能量主要积聚在近地表土层,并使得沉积内部地表位移幅值显著放大,地震动持时明显增长。另外,沉积谷地形状和入射角度对地震波聚焦特征也具有重要影响,不同波型入射下聚焦区域有很大差别。实际沉积谷地地震动场精确模拟需获取较为精细的地层波速结构和边界几何特征。
- 沉积谷地 /
- 地震响应 /
- FEM-IBIEM耦合法 /
- 地层波速模型
Abstract: Accurate wave velocity model is essential for site effect analysis, while there is large uncertainty in determining the actual wave velocity. The simplified homogeneous and layered model is usually adopted, or the wave velocity is assumed to vary linearly, quadraticly and exponentially according to the drilling data. However, the effect of different velocity models on seismic response of the alluvial valley is not clear. It is attempted to reveal the influence mechanism through quantitative analysis both in frequency and time domains using an accurate finite element-indirect boundary integral equation method. The numerical results show that for incident low-frequency waves (), different velocity models have little influence on the surface displacement amplitude. As the frequency increases, the influence becomes more and more significant. The difference between the linear model and homogeneous model is highlighted. It is found that the high-frequency resonance and the basin edge effect in the case of linear models seem more remarkable, which lead to the concentration of earthquake energy mainly in the near surface layer, the surface displacement amplitude in the valley is significantly enlarged, and the duration of earthquake ground motion increases obviously as well. In addition, the alluvial valley shape and the incident angle also have significant influence on the scattering characteristics of seismic waves, and the focusing area varies for different wave types. It is necessary to obtain wave velocity structure and boundary geometrical features of actual alluvial valley for the accurate simulation of earthquake ground motion.
- alluvial valley /
- seismic response /
- FEM-IBIEM coupling method /
- wave velocity model

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参考文献(17)

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不同地层波速模型对沉积谷地地震响应规律的影响：FEM-IBIEM模拟研究 English Version

作者简介: 刘中宪(1982- ),男,河南泌阳人,博士后,副教授,主要从事地震工程、工程波动领域的研究和教学工作。E-mail: zhongxian1212@163.com。

计量

出版历程

Effect of different wave velocity models on seismic response of alluvial valley based on FEM-IBIEM

计量

出版历程

目录

作者简介:
刘中宪(1982- ),男,河南泌阳人,博士后,副教授,主要从事地震工程、工程波动领域的研究和教学工作。E-mail: zhongxian1212@163.com。