Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compression
Internal erosion is a major threat to hydraulic earth structures, such as river levees and dams. This paper focuses on suffusion and suffosion phenomena which are caused by the movement of fine particles in the granular skeleton due to seepage flow. The present study investigates the impact of inter...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-12-01
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| Series: | Soils and Foundations |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0038080622001329 |
| _version_ | 1811181923811196928 |
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| author | Sanjei Chitravel Masahide Otsubo Makoto Kuno Reiko Kuwano |
| author_facet | Sanjei Chitravel Masahide Otsubo Makoto Kuno Reiko Kuwano |
| author_sort | Sanjei Chitravel |
| collection | DOAJ |
| description | Internal erosion is a major threat to hydraulic earth structures, such as river levees and dams. This paper focuses on suffusion and suffosion phenomena which are caused by the movement of fine particles in the granular skeleton due to seepage flow. The present study investigates the impact of internal erosion on the dynamic response under cyclic torsional shear and monotonic responses under triaxial compression and torsional simple shear. A series of experiments, using a gap-graded silica mixture with a fines content of 20%, is performed under loose, medium, and dense conditions using a novel erosion hollow cylindrical torsional shear apparatus. The erosion test results indicate that the critical hydraulic gradient and the rate of erosion are density-dependent, where a transition from suffosion to suffusion is observed as the seepage continues. Regardless of the sample density, variations in the radial strain and particle size distribution, along the specimen height after erosion, are no longer uniform. Furthermore, the dynamic shearing results show that the small-strain shear modulus increases, but the initial damping ratio decreases after internal erosion, probably due to the removal of free fines. In addition, the elastic threshold strain and reference shear strain values are found to be higher for the eroded and non-eroded specimens, respectively. Finally, based on drained monotonic loading, the post-erosion peak stress ratio increases remarkably under triaxial compression, while that under torsional simple shear depends on the relative density where the direction of loading is normal to the direction of seepage. These observations indicate that the horizontal bedding plane becomes weaker, while the vertical one becomes stronger after downward erosion. |
| first_indexed | 2024-04-11T09:25:07Z |
| format | Article |
| id | doaj.art-ccd319e5fab44dceb5c6610b0f3a52c1 |
| institution | Directory Open Access Journal |
| issn | 2524-1788 |
| language | English |
| last_indexed | 2024-04-11T09:25:07Z |
| publishDate | 2022-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Soils and Foundations |
| spelling | doaj.art-ccd319e5fab44dceb5c6610b0f3a52c12022-12-22T04:32:03ZengElsevierSoils and Foundations2524-17882022-12-01626101224Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compressionSanjei Chitravel0Masahide Otsubo1Makoto Kuno2Reiko Kuwano3Corresponding author.; Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanInstitute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanInstitute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanInstitute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanInternal erosion is a major threat to hydraulic earth structures, such as river levees and dams. This paper focuses on suffusion and suffosion phenomena which are caused by the movement of fine particles in the granular skeleton due to seepage flow. The present study investigates the impact of internal erosion on the dynamic response under cyclic torsional shear and monotonic responses under triaxial compression and torsional simple shear. A series of experiments, using a gap-graded silica mixture with a fines content of 20%, is performed under loose, medium, and dense conditions using a novel erosion hollow cylindrical torsional shear apparatus. The erosion test results indicate that the critical hydraulic gradient and the rate of erosion are density-dependent, where a transition from suffosion to suffusion is observed as the seepage continues. Regardless of the sample density, variations in the radial strain and particle size distribution, along the specimen height after erosion, are no longer uniform. Furthermore, the dynamic shearing results show that the small-strain shear modulus increases, but the initial damping ratio decreases after internal erosion, probably due to the removal of free fines. In addition, the elastic threshold strain and reference shear strain values are found to be higher for the eroded and non-eroded specimens, respectively. Finally, based on drained monotonic loading, the post-erosion peak stress ratio increases remarkably under triaxial compression, while that under torsional simple shear depends on the relative density where the direction of loading is normal to the direction of seepage. These observations indicate that the horizontal bedding plane becomes weaker, while the vertical one becomes stronger after downward erosion.http://www.sciencedirect.com/science/article/pii/S0038080622001329Internal erosionGap-graded soilTorsional simple shearTriaxial compressionIntergranular void ratio |
| spellingShingle | Sanjei Chitravel Masahide Otsubo Makoto Kuno Reiko Kuwano Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compression Soils and Foundations Internal erosion Gap-graded soil Torsional simple shear Triaxial compression Intergranular void ratio |
| title | Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compression |
| title_full | Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compression |
| title_fullStr | Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compression |
| title_full_unstemmed | Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compression |
| title_short | Post-erosion mechanical responses of internally unstable gap-graded soil under drained torsional simple shear and triaxial compression |
| title_sort | post erosion mechanical responses of internally unstable gap graded soil under drained torsional simple shear and triaxial compression |
| topic | Internal erosion Gap-graded soil Torsional simple shear Triaxial compression Intergranular void ratio |
| url | http://www.sciencedirect.com/science/article/pii/S0038080622001329 |
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