Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting Cycles
This research examined the drying–wetting cycles induced changes in undrained triaxial shear strength parameters and microstructural changes of Yili loess. The drying–wetting cycles were selected as 0, 1, 3, 5, 10, 20 and 30. Then, we collected Yili loess samples and performed unconsolidated-undrain...
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| Online Access: | https://www.mdpi.com/1996-1944/15/1/255 |
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| author | Ruihua Hao Zizhao Zhang Zezhou Guo Xuebang Huang Qianli Lv Jiahao Wang Tianchao Liu |
| author_facet | Ruihua Hao Zizhao Zhang Zezhou Guo Xuebang Huang Qianli Lv Jiahao Wang Tianchao Liu |
| author_sort | Ruihua Hao |
| collection | DOAJ |
| description | This research examined the drying–wetting cycles induced changes in undrained triaxial shear strength parameters and microstructural changes of Yili loess. The drying–wetting cycles were selected as 0, 1, 3, 5, 10, 20 and 30. Then, we collected Yili loess samples and performed unconsolidated-undrained (U-U) triaxial shearing tests to ascertain the variation in shear strength parameters with drying–wetting cycles. Additionally, we investigated the microstructural changes of Yili loess samples under drying–wetting cycles simultaneously via nuclear magnetic resonance (NMR) and scanning electron electroscopy (SEM). Finally, we established a grey correlation model between shear strength and microstructural parameters. Under U-U conditions, the prime finding was that the loess’s shear strength parameters changed overall after drying–wetting cycles; in particular, the internal friction angle φ dropped significantly while the cohesion c changed only slightly during cycles. For all the cycles, the first cycle gave the highest change. Soil morphology deterioration was evident at the initial stage of cycles. During the entire drying–wetting cyclic process, pore size distribution showed progressive variance from two-peak to a single-peak pattern, while both porosity and the fractal dimension of pores increased gradually towards stability. Soil particle morphology became slowly simple and reached the equilibrium state after 20 drying–wetting cycles. Under cyclic drying–wetting stress, the shear strength parameter changes were significantly correlated to microstructural modifications. This investigation was related to loess in the westerly region. The findings were expected to provide new insight into establishment of the connection between microstructure and macro stress–strain state of loess. To some extent, it provided a theoretical basis for the prevention and control of loess engineering geological disasters in Yili, Xinjiang and other areas with similar climate and soil types. |
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| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T03:33:46Z |
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| spelling | doaj.art-660a603c0c2b422ca598e2068734aba22023-11-23T11:50:32ZengMDPI AGMaterials1996-19442021-12-0115125510.3390/ma15010255Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting CyclesRuihua Hao0Zizhao Zhang1Zezhou Guo2Xuebang Huang3Qianli Lv4Jiahao Wang5Tianchao Liu6School of Geological and Mining Engineering, Xinjiang University, Urumqi 830017, ChinaSchool of Geological and Mining Engineering, Xinjiang University, Urumqi 830017, ChinaSchool of Geological and Mining Engineering, Xinjiang University, Urumqi 830017, ChinaSchool of Geological and Mining Engineering, Xinjiang University, Urumqi 830017, ChinaSchool of Geological and Mining Engineering, Xinjiang University, Urumqi 830017, ChinaSchool of Geological and Mining Engineering, Xinjiang University, Urumqi 830017, ChinaThe First Regional Geological Survey Brigade, Xinjiang Bureau of Geo-Exploration and Mineral Development, Urumqi 830011, ChinaThis research examined the drying–wetting cycles induced changes in undrained triaxial shear strength parameters and microstructural changes of Yili loess. The drying–wetting cycles were selected as 0, 1, 3, 5, 10, 20 and 30. Then, we collected Yili loess samples and performed unconsolidated-undrained (U-U) triaxial shearing tests to ascertain the variation in shear strength parameters with drying–wetting cycles. Additionally, we investigated the microstructural changes of Yili loess samples under drying–wetting cycles simultaneously via nuclear magnetic resonance (NMR) and scanning electron electroscopy (SEM). Finally, we established a grey correlation model between shear strength and microstructural parameters. Under U-U conditions, the prime finding was that the loess’s shear strength parameters changed overall after drying–wetting cycles; in particular, the internal friction angle φ dropped significantly while the cohesion c changed only slightly during cycles. For all the cycles, the first cycle gave the highest change. Soil morphology deterioration was evident at the initial stage of cycles. During the entire drying–wetting cyclic process, pore size distribution showed progressive variance from two-peak to a single-peak pattern, while both porosity and the fractal dimension of pores increased gradually towards stability. Soil particle morphology became slowly simple and reached the equilibrium state after 20 drying–wetting cycles. Under cyclic drying–wetting stress, the shear strength parameter changes were significantly correlated to microstructural modifications. This investigation was related to loess in the westerly region. The findings were expected to provide new insight into establishment of the connection between microstructure and macro stress–strain state of loess. To some extent, it provided a theoretical basis for the prevention and control of loess engineering geological disasters in Yili, Xinjiang and other areas with similar climate and soil types.https://www.mdpi.com/1996-1944/15/1/255drying–wetting cyclesyili loesstriaxial shearing parametersnuclear magnetic resonance (NMR)scanning electron microscopy (SEM) |
| spellingShingle | Ruihua Hao Zizhao Zhang Zezhou Guo Xuebang Huang Qianli Lv Jiahao Wang Tianchao Liu Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting Cycles Materials drying–wetting cycles yili loess triaxial shearing parameters nuclear magnetic resonance (NMR) scanning electron microscopy (SEM) |
| title | Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting Cycles |
| title_full | Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting Cycles |
| title_fullStr | Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting Cycles |
| title_full_unstemmed | Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting Cycles |
| title_short | Investigation of Changes to Triaxial Shear Strength Parameters and Microstructure of Yili Loess with Drying–Wetting Cycles |
| title_sort | investigation of changes to triaxial shear strength parameters and microstructure of yili loess with drying wetting cycles |
| topic | drying–wetting cycles yili loess triaxial shearing parameters nuclear magnetic resonance (NMR) scanning electron microscopy (SEM) |
| url | https://www.mdpi.com/1996-1944/15/1/255 |
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