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An advanced Research on the Structural Dynamics due to Short-Period Surface Waves with Emphasis on Applications to Practice

注重应用实践的短周期面波结构动力学研究进展

基本信息

批准号：
13650530
负责人：
KAMIYAMA Makoto
金额：
$ 2.43万
依托单位：
Tohoku Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

We have developed, some softwares for the earthquake response analysis of horizontally irregular grounds using the Pseudo-spectural method. Especially emphasis was placed on the introduction of nonlinear characteristics of soils as well as on the sophistications of programs. For the purpose of applications of our softwares to practice, we selected the irregular ground in Sendai City as a test site. Sendai City suffered severe damage due to the 1978 Miyagiken-Oki Earthquake. Since the earthquake, Sendai City has extended into areas composed of softer soils, increasing the anxieties of more devastating disaster by a great earthquake in the near future. In order to investigate strong-ground motions in Sendai, we installed there an array observation system of ground motions in 1997. The array system, named Snall-Titan, consists of 20 observation stations and one control center. Stimulated by the high seismicity in the Sendai district, the system has obtained many motion records resulting from a total of 250 earthquakes as of February in 2004. We first discussed observation results of ground motions in the Sendai basin from the point of view of local site effects, showing that amplifications of ground motions vary from site to site and arc remarkable in the soft deposit areas of the basin. The differences in amplifications between locations of the soft deposit areas were also analyzed. This analysis led to the importance of the edge effects of basin structure on the ground motions of the soft deposit areas. In order to make clear the mechanism of the edge effects, we modeled the Sendai basin using a two-dimensional Pseudo-Spectral Method. Based on-the model of basin structure, we made two-dimensional analyses of ground motions and compare the analyzed results with the observed. Comparisons show that the edge effects play an important role in amplifying motions in the soft deposit area of basin structure.

本文利用拟谱法编制了水平不规则场地地震反应分析软件。着重介绍了土的非线性特性及程序的编制。为了将软件应用于实践，我们选择了仙台市的不规则地面作为试验场地。1978年宫城县大地震导致仙台市遭受严重破坏。地震发生后，仙台市已经延伸到由软土组成的地区，增加了人们对不久的将来发生大地震造成更大破坏性灾难的担忧。为了调查仙台地区的强地震动，我们于1997年在那里安装了一个地震动阵列观测系统。该阵列系统名为Snall-Titan，由20个观测站和一个控制中心组成。在仙台地区高地震活动的刺激下，该系统获得了许多运动记录，截至2004年2月，共250次地震。本文首先从场地效应的角度讨论了仙台盆地的地震动观测结果，指出地震动的放大效应因场地而异，在盆地的软存款区尤为显著。分析了软存款区不同位置的放大率差异。这一分析导致了盆地结构的边缘效应对软存款地区的地震动的重要性。为了弄清边缘效应的机制，我们用二维伪谱方法模拟了仙台盆地。根据盆地结构模型，对二维地震动进行了分析，并将分析结果与实测结果进行了比较。对比表明，在盆地构造的软存款区，边缘效应对运动放大起着重要作用。