Study on factors affecting liquefaction characteristics of sandy deposits considering issues arose after the 2011 off Pacific Coast of Tohoku Earthquake

2014 Fiscal Year Final Research Report

• Project/Area Number: 24360189
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Geotechnical engineering
• Research Institution: The University of Tokyo
• Principal Investigator: KIYOTA Takashi 東京大学, 生産技術研究所, 准教授 (70431814)
• Co-Investigator(Renkei-kenkyūsha): KONAGAI Kazuo 横浜国立大学, 大学院都市イノベーション学府, 教授 (50126471)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 液状化 / 三軸試験 / 微小変形特性 / 地盤改良 / フライアッシュ / ハザードマップ / 不攪乱試料

Outline of Final Research Achievements

This study investigated issues on soil liquefaction after the 2011 off Pacific Coast of Tohoku Earthquake based on comprehensive laboratory tests. The aging effects of soils on liquefaction and small strain characteristics were investigated. A rational liquefaction assessment method could be developed based on not only SPT-N value but also the small strain characteristics. In addition, we pointed out a problem of current liquefaction assessment with an undisturbed soil sample taken by conventional tube sampling method. This study also verified experimentally the effects of flyash on liquefaction resistance buildup and excavatability of the improved soil. Finally, we conducted a simple liquefaction assessment in Urayasu city, and the relationship between liquefaction potential and road subsidence were extracted based from the DSMs. Based on the result, an attempt was made to apply the obtained PL and road subsidence relations to attain a unique hazard map.

Free Research Field

地盤工学