2020 Fiscal Year Final Research Report
interpretation of macroscopic response of partially saturated soil by clarifying microscopic characteristics of pore fluids
| Project/Area Number |
19K23534
|
|---|
| Research Category |
Grant-in-Aid for Research Activity Start-up
|
| Allocation Type | Multi-year Fund |
|---|
| Review Section |
0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2019-08-30 – 2021-03-31
|
| Keywords | 不飽和土 / 間隙水 / 間隙空気 / X線CT / 画像解析 / 排水条件 / 排気条件 / 軸差応力 |
|---|
| Outline of Final Research Achievements |
The effect of the three-phase microstructure on the macroscopic response of an unsaturated soil consisting of soil particles, water and air was investigated using X-ray CT and image analysis.
The results showed that the number of liquid bridges between soil particles decreased during shear deformation of partially saturated soil. In the undrained condition for water where the suction decreases during deformation, the number of liquid bridges decreases more than in the drained condition for water, where the suction remains constant, resulting in a decrease in the axial differential stress.
The results also suggest that the behavior is more brittle in the undrained condition for air compared to the case where the air pressure is kept at atmospheric pressure. On the other hand, the validity of the behavior under undrained condition for air remains to be examined.
|
| Free Research Field |
地盤工学
|
| Academic Significance and Societal Importance of the Research Achievements |
これまで不飽和土の変形・破壊メカニズムを，軸差応力の大小や供試体の変形モードといったマクロな視点から検討する研究はあったものの，そのようなマクロな応答を司るミクロな挙動の解明に着目し，異なるスケールの挙動のリンクさせる研究は世界的に見ても例がなく，学術的な意義は大きい．
道路や斜面などの不飽和土構造物の設計，施工においては，不飽和土の強度や剛性を事前に評価することが重要である．本研究の研究成果は，不飽和土の強度・変形特性が土の含水状態や変形条件によって異なるメカニズムを解釈し，実際にどういった実験条件を設定し強度評価すればよいかの参考となる点で，社会的意義は大きいといえる．
|
