DEVELOPMENT OF SHEAR WAVE VELOCITY EXPLORATION SYSTEM BASED ON MICROTREMOR MEASUREMENTS AND IT'S APPLICATION TO SITE CHARACTERISTCS

基于微动测量的剪切波速度探测系统开发及其在场地特征中的应用

基本信息

批准号：
10555197
负责人：
TOKIMATSU Kohji
金额：
$ 3.46万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The objects of this study is to develop a technique for estimating shear wave velocity structures using both the dispersion characteristics and the H/V spectra that can readily be obtained from microtremor measurements and to examine it's application for the evaluation of dynamic response characteristics of a site. For this purpose, (1), analytical formulas are presented for computing the H/V ratios of microtremors, assuming, that microtremors consist of Rayleigh and surface waves, (2) an inverse analysis using H/V spectra is developed for estimating a shear wave velocity structure under appropriate constraint conditions, (3) a theory and a field technique as well as observation system are introduced for estimating two-dimensional shear wave velocity structure using both microtremor dispersion curve and H/V spectra, (4) the effectiveness of the proposed method is examined based on microtremor measurements at sites for which shear, wave velocity structure is available, and (5) dynamic r … More esponse analyses are conducted using the two-dimensional shear wave velocity structures that are estimated from the proposed method for the regions where either strong motion array records or spatial variation of damage was obtained during the Kushiro-oki and Hyogoken-Nambu earthquakes.It is shown that:(1) The H/V ratios of surface waves are in fairly good agreement with those of microtremors;(2) VィイD2sィエD2 profiles of subsurface soils may be estimated from the H/V ratios of microtremors using the proposed formulas,.(3) The microtremor measurements in Kushiro and Kobe confirm the effectiveness of the proposed method for outlining three-dimensional soil profiles with varying thickness of surface layer overlying bedrock, and(4) The computed spatial variation in acceleration from two-dimensional shear wave velocity structures estimated from microtremors are consistent with those observed in the field, indicating that the effectiveness of an economical means of estimating two- or three-dimensional shear structure Less

本研究的目的是开发一种使用色散特性和 H/V 谱（可从微震测量中轻松获得）来估计剪切波速度结构的技术，并检验其在评估场地动态响应特性方面的应用为此，(1) 提出了计算微震 H/V 比的解析公式，假设微震由瑞利波和表面波组成，(2) 开发了使用 H/V 谱的反演分析在适当的约束条件下估计剪切波速度结构，（3）介绍了使用微震色散曲线和 H/V 谱估计二维剪切波速度结构的理论和现场技术以及观测系统，（4）所提出方法的有效性是基于在剪切波速结构可用的地点进行的微震测量来检验的，并且（5）使用二维剪切波速结构进行动态响应分析，该二维剪切波速结构是从该方法针对钏路大地震和兵库县南部地震期间获得强震阵列记录或损伤空间变化的区域。结果表明：(1)面波的H/V比值较好。与微动的一致；(2) 地下土壤的 ViiD2 剖面可以使用所提出的公式根据微动的 H/V 比来估计。(3) 微动测量钏路和神户证实了所提出的方法对于勾画具有变化的基岩表面层厚度的三维土壤剖面的有效性，并且（4）根据微震估计的二维剪切波速度结构计算出的加速度空间变化与那些在现场观察到的结果，表明估计二维或三维剪切结构的经济方法的有效性 Less