Effect of Liquefaction on Lifeline Facilities and Earthquake Resistant Design

本课题的主要研究内容如下：(1)液化土的行为与特性研究利用日本和美国多个研究所的试验和数值分析结果，对液化土的行为与特性进行了全面的研究，特别是对液化土作为粘性液体的特性进行了研究。(2)液化诱发地面位移预测的计算机试验程序的开发液化诱发地面位移的震级和分布的计算机试验程序是在日美两国合作下开发的。合作。采用有限元法和边界元法进行的数值分析结果与日本振动台试验结果吻合较好。此外，试验程序还获得了数值结果与实际地面观测到的地面侧向位移吻合较好的结果。利用美国开发的ARCH INFO（GIS）系统，研究了1964年新潟地震和1983年日本海—中部地震中液化引起的地面大位移的特征。研究发现，地面从高海拔向低海拔移动，但地面位移的大小与地面坡度之间没有明显的定量相关性。(4)抗液化对策的研究提出了在地下结构上设置带撑杆的膜墙作为抗液化对策。通过日本振动台试验和美国数值试验验证了该方法的有效性

The main content of this research project can be summarized as follows:(1)Study on Behavior and Characteristics of Liquefied SoilThe behaviors and characteristics of the liquefied soil were totally investigated by using the results of experiments and numerical analyses, which had been conducted in various institutes in Japan and U.S.A. For particular the properties of the liquefied soil as a viscous liquid was investigated.(2)Development of A Pilot Computer Program to Predict Liquefaction-Induced DisplacementA Pilot computer program to predict the magnitude and the distribution of the liquefaction- induced ground displacement was developed under Japan-U.S. cooperation. The result from the numerical analyses by using the technique of the Finite Element Method(FEM) and the Boundary Element Method (BEM) well coincided with the one from shaking tabke tests, which had been conducted in Japan. Furthermore, the pilot program also obtained a good coincidence between numerical result and lateral ground displacements observed in an actual ground.(3)Analysis of Liquefaction-Induced Ground Displacement by GIS(Geographical Information System)By using ARCH INFO(GIS), which had been developed in U.S., the characteristics of the liquefaction-induced large ground displacement during the 1964 Niigata and the 1983 Nihonkai- Chubu earthquakes was investigated. It was examined that the ground moved from the higher elevation to the lower elevation, but any clear quantitative correlation was not found between the magnitude of the ground displacement and the gradient of the grond surface.(4)Study on Countermeasure against LiquefactionA Countermeasure, where a membrane wall with supporting poles was constructed in the ground, was proposed up of inground structures during liquefaction. The effectiveness of the proposed method was verified by shaking table tests in Japan and numerical examination in U.S.