Liquefaction Analysis of Reclamation Dike during Earthquake

围垦堤防地震液化分析

• 批准号: 60560249
• 负责人: YOSHITAKE Yoshitaka
• 金额: $ 0.83万
• 依托单位: Ehime University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60560249/
• 关键词: Reclamation Dikes; Seismic Risk Analysis; Liquefaction; Reclamation In Water Area; 干拓

There are eighty-eight reclamation dikes in the Chugoku,Shikoku and Kyushu region which have been completed after the Second World War. Twenty-eight of these dikes and forty-one of these foundation grounds consist of sandy soil. Seismic risk analysis were carried out for all construction sites by making use of the attenuation equations which were established by Research Institute,Ministry of Construction. From this analysis, the 100-year earthquake motion was calculated and three district(Miyazaki,Miike,Tokushima) had the value more than 100 gal, five districts (Takehara,Kojima,Yonago,Kokubu,Nishikunisaki) had the value no more than 100 gal but no less than 80 gal and the others had the value no more than 80 gal.Liquefaction analysis by Research Institute,Ministry of Construction's method were carried out by using the 100-year earthquake motion,stamdard penetration value(N-value), blueprins, soil explorations and groundwater level. First, this cnalysis was applied to ground models which have different N-vaiues, groundwater levels, grain sizes and specific gravities, then, to each dikes which consist of sandy soil and safty factors were calucated. When the condition of soil and ground become worse,few of them were less than 1.0. But, these happening depths from dike crests were deeper than 6.0m and,moreover,these dikes and foundation ground must consit of more fine soil in practical ploblems,accordingly from these results of liquefaction analysis for the 100-year earthquake motion, it was concluded that these dikes will be in safety. Finally,there was no dikes which was damaged by earthquake during these forty years.

中国、四国和九州地区有 88 条填海堤是在第二次世界大战后完成的。其中 28 座堤坝和 41 座基础地面由沙土组成。利用建设部研究院建立的衰减方程对所有施工场地进行了地震风险分析。根据此分析，计算出 100 年地震运动，三个地区（宫崎、三池、德岛）的值超过 100 加仑，五个地区（竹原、小岛、米子、国分、西国崎）的值不超过 100加仑但不少于80加仑，其他数值不超过80加仑。部研究所液化分析施工方法是利用100年地震、标准贯入值（N值）、图纸、土壤勘探和地下水位进行的。首先，将该分析应用于具有不同N值、地下水位、粒度和比重的地面模型，然后，对由沙土组成的每条堤坝进行安全系数计算。当土壤和地面状况变差时，很少会低于1.0。但是，这些距堤顶的发生深度都超过了6.0m，而且在实际问题中，这些堤坝和基础地面必须由更细的土组成，因此从10​​0年地震液化分析的结果可以得出结论这些堤坝将是安全的。最后，这四十年来，没有任何堤坝因地震而受损。