Joint Study on Urban Seismic Disaster of Irregular Site

在不规则场地城市地震灾害联合研究中，研究了不规则地形场地对地震动特性和城市地震灾害的影响。研究的第一部分是在中国（同济大学）和日本（丰桥工业大学）进行的地震动观测。分析结果表明，无论输入地震动如何，如震中位置、入射方向和震级，不同地震的谱比对单个观测点都表现出相同的趋势。为了比较观测结果与理论结果的放大效应，根据实际地基条件，采用一维和二维模型进行了分析。结果表明，入射波的方向和入射角对放大率的影响不大，而受地形条件的影响较大。根据轴对称河谷的响应分析， ...更多信息 艾德发现：a）对应的放大率在谷中心处最大，向谷边缘减小; B）基本共振频率只取决于谷中心处的一维频率和形状比两个参数，而与入射波场和阻抗对比度无关。所提出的经验公式可以准确地估计基频。c）谷中心处的基频谐振幅度取决于形状比和阻抗对比度。第二部分考虑了城市地区（上海和东京）地震危险性的估计。运用概率方法，分析了地震时道路和建筑物的倒塌和火灾对道路和建筑物的破坏的影响。从地震疏散风险评价结果来看，居民疏散风险受人口密度、道路和街道故障以及避难岛数量的影响。通过对上海历史地震、地基条件和房屋建筑结构特征的研究，发现上海的地震危险性低于东京。少

In the joint study on urban seismic disaster of irregular site, the effects of irregular topography site in behavior of ground motions and urban seismic disasters are investigated. The first part of the study the seismic motion observation in China (Tongji University) and Japan(Toyohashi University of Technology) were carried out. From the analysis the results showed the spectral ratios of different earthquake indicate the same tendency for individual observation point regardless of the input earthquake motion, such as the epicenter, incident direction and the magnitude. In order to compare the amplification effects of the observational results and theoretical results, the analysis based on the actual ground conditions has been performed by using 1-dimensional and 2-dimensional model. It was found that the amplification was not influenced very much by the direction and angle of incident wave but by the topographical conditions. From the response analyses of axisymmetric valleys subject … More ed to incident waves, it found thata) The corresponding amplification is maximum at the valley center and decreases toward the edges.b) The fundamental resonance frequencies depend only on two parameters, namely, the onedimensional frequency at the valley center and the shape ratio, regardless of the incident wave field and the impedance contrast. The proposed empirical formulas can estimate accurately the fundamental frequencies.c) The fundamental resonance amplitudes at the valley center depend on the shape ratio and the impedance contrast. The proposed empirical formulas can estimate approximately the fundamental resonance amplitudes.In the second part the estimation of earthquake risk in urban areas (Shanghai and Tokyo) are considered. By the using the probabilistic method, the malfunction of the roads and streets during earthquake were influenced by the collapse of houses and building and the destruction of them by fire. From earthquake evacuation risk evaluation, the results showed that the evacuation risks of inhabitants were influenced by population density, the malfunction of the roads and streets and number of refuge islands. And in the study the past histrical earthquakes, subsoil conditions and structural characteristics of residential houses and building , it was found that the earthquake risk in Shanghai were lower than in Tokyo. Less