Study of Earthquake Disaster Prevention of Waterfront

滨水区地震防灾研究

基本信息

批准号：
01302044
负责人：
HAMADA Masanori
金额：
$ 8.32万
依托单位：
Tokai, University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

The summary of the results of the present research is as follows ;(i) It was pointed out based on the state of the art on lifeline performance in reclaimed ground during past earthquakes that specific research subjects such as earthquake motion in the neighborhood of fault, dynamic response of soft ground, liquefaction-induced ground displacement and its effect on buried lifeline facilities should be proceeded to create earthquake-proof urban societies in waterfronts in Japan.(ii) Liquefaction can cause several kinds of damage to lifeline structures ; settlement and tilting of structures due to reduction of bearing capacity of ground, floating of buried structures due to the buoyancy of the liquefied soil, collapse of quay walls and retaining walls due to earth pressure increase, failure of earth structures like embankment, and damage to liquefaction-induced large ground displacement.(iii) The liquefaction-induced ground displacements were found during ten past earthquakes in Japan as … More well as in United States. The ground displacements were oriented from sand dunes and natural levees with a little higher elevation towards old streams of big rivers with a lower elevation. The maximum ground displacement reached over 12 m during the 1964 Niigata earthquake.(iv) The magnitude of the ground displacement has a close correlation with the thickness of the liquefied layer, but not with the gradient of the ground surface. The mechanism of the occurrence of the liquefaction-related large ground displacement has not been clarified. Therefore, more studies on case histories of ground displacement, numerical analyses, experimental studies are required.(v) The liquefaction-induced ground displacement caused severe damage to buried structures such as foundation piles and pipelines. It was conjectured from examination of damaged structures and experimental studies that a drag force of liquefied soil was applied to the buried structures.(vi) A method to prevent liquefaction-induced ground displacement, where flexible inground walls are constructed in liquefiable soil, was proposed and its effectiveness was verified by shaking table tests. Less

本研究结果总结如下：(i)根据过去地震期间填海地生命线性能的最新进展，指出断层附近的地震运动等具体研究课题，应研究软土地基的动力响应、液化引起的地面位移及其对埋藏生命线设施的影响，以在日本滨水区创建抗震城市社会。（ii）液化会对生命线结构造成多种损坏；结构的由于地面承载力降低，液化土的浮力导致埋地结构上浮，土压力增大导致岸墙、挡土墙倒塌，路堤等土结构物破坏，液化引起大面积地面破坏等。 (iii) 在日本和美国过去的十次地震中都发现了液化引起的地面位移，地面位移是从海拔稍高的沙丘和天然堤坝向的。 1964年新泻地震时，地表位移最大达12m以上。(iv)地表位移大小与液化层厚度有密切关系，但与坡度无关。液化相关大地面位移的发生机制尚未明确，因此需要更多的地面位移实例研究、数值分析和实验研究。液化引起的地面位移对基桩、管道等埋地结构造成严重破坏。通过对受损结构的检查和试验研究推测，液化土对埋地结构施加了拖曳力。(vi)防止埋地结构的方法。提出了液化引起的地面位移，即在可液化土壤中建造柔性地下墙，并通过振动台试验验证了其有效性。