Development of evaluation technique of seismic capacity for earth dam considering loading history

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K21610
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Rural environmental engineering/Planning; Geotechnical engineering
• Research Institution: Shimane University
• Principal Investigator: UENO Kazuhiro 島根大学, 学術研究院環境システム科学系, 助教 (60560167)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 繰返し載荷履歴 / 動的強度 / ひずみ履歴 / せん断波速度

Outline of Final Research Achievements

Seismic capacity of earth dams would be varied due to effects of loading histories such as damage to soil structure by earthquakes. To evaluate how multiple loading histories of pre-shearing strain of various magnitudes affect resistance against undrained cyclic loading of soil, multistage cyclic triaxial tests under undrained conditions were performed. When pre-shearing strain is less than 1%, the resistance increased as the loading stage progresses, whereas a large pre-shearing strain decreased the resistance. However, even upon imposing a large pre-shearing strain on a specimen, the resistance did not decrease if the specimen has already experienced a similar pre-shearing strain in a previous loading stage. On the other hand, it was confirmed that shear wave velocity of soil could be an index to evaluate the resistance of soil varying according to loading histories.

Free Research Field

地域環境工学・計画学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的意義は、複数の繰返し載荷履歴の経験が土の動的強度に与える影響や、再圧密中の動的強度の変化傾向など、被災履歴に伴うため池堤体の耐震性の変化に影響を与える要因を明確化したことである。また、繰返し載荷履歴に伴って変化する動的強度と、ため池現地で観測可能なせん断波速度の相関関係を示した。これにより、せん断波速度を指標としたため池堤体の耐震性評価の高度化が期待でき、安全な農村環境の構築へ貢献できると考えられる。