Reproduction of delayed failure due to liquefaction considering the effect of non-liquefiable layer

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04604
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: Nihon University
• Principal Investigator: SENTO Noriaki 日本大学, 工学部, 教授 (40333835)
• Co-Investigator(Kenkyū-buntansha): 海野 寿康 宇都宮大学, 地域デザイン科学部, 准教授 (50570412)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 液状化 / 遅れ破壊 / 非液状化層 / 過剰間隙水圧 / 被圧

Outline of Final Research Achievements

In this study, delayed ground failure due to liquefaction, which has been difficult to reproduce, is reproduced via a shaking model test. Two conditions to reproduce delayed failure are discovered in this study. First, the liquefied layer comprising extremely loose sand is coated by an impermeable layer, and the pore water pressure must be maintained relatively high in the liquefied layer. Second, a driving force, such as an inclined slope, must be maintained such that the ground deforms after shaking. Excess pore water pressure exceeding the initial effective overburden pressure is observed in the vicinity of the impermeable layer.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

難透水層を一部に含む非液状化層が液状化に及ぼす影響を詳細に検討した研究は、国内外を含めて例がなく、液状化後の時間遅れ破壊メカニズムの根本的な解明に資する知見を得ることができた。加えて、これまで再現が困難であった時間遅れ破壊現象を模型振動実験で再現するための実験条件を明確にした。本研究成果を活用して模型振動実験を実施することで、合理的かつ経済的な液状化対策開発のヒントを与えるものと期待される。