Loma Prieta Earthquake: Response of San Francisco Bay Deep Fill Deposits to Cyclic Loading

该研究项目是收集1989年10月17日北加州（洛马·普里塔）地震的易腐数据倡议的一部分。研究发现，场地的具体岩土条件和软土厚度对地震时的损伤分布和视震动强度有显著影响。地震发生后，美国地质调查局（USGS）立即在旧金山和奥克兰受灾最严重的地区，在地表和基岩顶部的深钻孔中安装了强震仪器。在钻井作业期间，从土壤剖面内所有重要地质单元中回收了未受干扰的土壤样品。这些样本包含的信息可用于进行现场反应的全面动态分析，包括现场反应的死后调查，以及预测未来对强烈地面震动的反应。本研究的目的是通过对这些土壤样品进行适当的分类试验和动态响应试验来获得这些信息，并将这些信息与美国地质勘探局获得的原位剪切波速测量结果相结合：这将导致对土壤沉积物动态响应特性的全面描述。结果将以包含完整应力-应变数据以及作为应变函数的导出模量和阻尼比的报告的形式呈现。

This research program is part of the initiative to collect perishable data resulting from the 17 October 1989 Northern California (Loma Prieta) earthquake. It was observed that the specific geotechnical conditions at a site and the thickness of the soft soil deposits had a significant influence on the distribution of damage and apparent intensity of shaking during the earthquake. Immediately following the earthquake, the U.S. Geological Survey (USGS) undertook the installation, in the most severely damaged areas of San Francisco and Oakland, of strong motion instruments on the ground surface and in deep boreholes on top of bedrock. Undisturbed soil samples were recovered from all the significant geologic units within the soil profile during the drilling operations. These samples contain information that can be used to perform full dynamic site response analyses for both post-mortem investigations of the site response, and for prediction of the future response to strong ground shaking. The objective of this study is to obtain this information through appropriate classification tests and dynamic response tests performed on these soil samples, and to combine this information with in-situ shear wave velocity measurements obtained by the USGS: this will result in a full description of the dynamic response characteristics of the soil deposit. The results are to be presented as a report containing the complete stress-strain data as well as the derived modulus and damping ratio as a function of strain.