Reconstruction of soil mechanics to describe the geomaterials mainly containing expansive minerals

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K14307
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geotechnical engineering
• Research Institution: Meijo University
• Principal Investigator: Kodaka Takeshi 名城大学, 理工学部, 教授 (00252271)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: ベントナイト / 三軸試験 / 膨潤性鉱物 / モンモリロナイト

Outline of Final Research Achievements

In this study, a series of triaxial tests using bentonite specimens was performed under various moisture conditions to study the mechanical properties of geomaterials containing a large amount of expansive minerals such as bentonite buffer materials used for radioactive waste disposal. It was also conducted to study the applicability of effective stress used in conventional soil mechanics.
As a result, it was shown that the influence of suction is large on the deformation and strength properties of bentonite buffer material, and the concept of effective stress does not hold. In addition, for bentonite buffer materials in saturated condition, the applicability of concept of effective stress was shown through numerical simulation, even for problems with large deformation such as triaxial test and direct shear test.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

種々の飽和度ならびに応力条件下におけるベントナイト緩衝材の系統的な三軸試験を実施し，そのダイレイタンシー特性を含む変形・強度特性を明らかにし，さらに，飽和度に応じた変形・強度特性の変化は，膨潤性鉱物特有の高いサクションの影響であることを示したことの学術的な意義は大きい。また，不飽和条件下での従来の有効応力の適用限界を示しつつ，その一方で飽和条件のベントナイトであれば，有効応力をベースとした数値シミュレーションによって緩衝材の大変形時の挙動予測までできることを示したことの社会的な意義は大きい。