Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine Sand
The small-strain stiffness of soil is significant in the accurate prediction of the deformation caused by interactions between foundation soil and structures. Considering the whole range of small strain (10<sup>−6</sup>~10<sup>−3</sup>), a bending element-resonant column (BE-...
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MDPI AG
2022-08-01
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| Online Access: | https://www.mdpi.com/2076-3417/12/17/8743 |
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| author | Kai Yan Yong Wang Zhiyong Yang Xianghua Lai Cheng Chen |
| author_facet | Kai Yan Yong Wang Zhiyong Yang Xianghua Lai Cheng Chen |
| author_sort | Kai Yan |
| collection | DOAJ |
| description | The small-strain stiffness of soil is significant in the accurate prediction of the deformation caused by interactions between foundation soil and structures. Considering the whole range of small strain (10<sup>−6</sup>~10<sup>−3</sup>), a bending element-resonant column (BE-RC) combined test system was developed to conduct continuous tests on the shear modulus of unsaturated soil. Under the dehydration path, it was used to investigate the small-strain shear modulus of unsaturated silty-fine sand in Hangzhou Bay, China. The results show that the shear modulus under different net stresses and matrix suctions appeared to non-linearly decay with the increase in strain until stable values were reached at a large strain. At the beginning from the saturated state, the <i>G<sub>max</sub></i> value increased slowly with decreasing saturation and reached its maximum value at the optimum saturation (<i>S<sub>r</sub></i>)<i><sub>opt</sub></i>; then, it rapidly decayed to the level in the saturated, once the saturation degree decreased to a level lower than (<i>S<sub>r</sub></i>)<i><sub>opt</sub></i>. Additionally, an improved prediction model was proposed for the <i>G<sub>max</sub></i> of unsaturated sand, considering different saturations. Based on the mesoscopic evolution of internal pore water morphology and the variation in intergranular stress caused by capillary action, the variation in the <i>G<sub>max</sub></i> could be divided into three segments of saturation: the boundary effect stage, the transition stage and the unsaturated residual stage. |
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| id | doaj.art-74cf11a4f7f04a7aa182023c47a4ad7d |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T03:01:47Z |
| publishDate | 2022-08-01 |
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| series | Applied Sciences |
| spelling | doaj.art-74cf11a4f7f04a7aa182023c47a4ad7d2023-11-23T12:46:11ZengMDPI AGApplied Sciences2076-34172022-08-011217874310.3390/app12178743Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine SandKai Yan0Yong Wang1Zhiyong Yang2Xianghua Lai3Cheng Chen4State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaAcademy of Railway Sciences Engineering Consult Co., Ltd., Beijing 100081, ChinaSecond Institute of Oceanography, MNR, Hangzhou 310012, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaThe small-strain stiffness of soil is significant in the accurate prediction of the deformation caused by interactions between foundation soil and structures. Considering the whole range of small strain (10<sup>−6</sup>~10<sup>−3</sup>), a bending element-resonant column (BE-RC) combined test system was developed to conduct continuous tests on the shear modulus of unsaturated soil. Under the dehydration path, it was used to investigate the small-strain shear modulus of unsaturated silty-fine sand in Hangzhou Bay, China. The results show that the shear modulus under different net stresses and matrix suctions appeared to non-linearly decay with the increase in strain until stable values were reached at a large strain. At the beginning from the saturated state, the <i>G<sub>max</sub></i> value increased slowly with decreasing saturation and reached its maximum value at the optimum saturation (<i>S<sub>r</sub></i>)<i><sub>opt</sub></i>; then, it rapidly decayed to the level in the saturated, once the saturation degree decreased to a level lower than (<i>S<sub>r</sub></i>)<i><sub>opt</sub></i>. Additionally, an improved prediction model was proposed for the <i>G<sub>max</sub></i> of unsaturated sand, considering different saturations. Based on the mesoscopic evolution of internal pore water morphology and the variation in intergranular stress caused by capillary action, the variation in the <i>G<sub>max</sub></i> could be divided into three segments of saturation: the boundary effect stage, the transition stage and the unsaturated residual stage.https://www.mdpi.com/2076-3417/12/17/8743unsaturated soilsandresonance columnbending elementsmall strainshear modulus |
| spellingShingle | Kai Yan Yong Wang Zhiyong Yang Xianghua Lai Cheng Chen Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine Sand Applied Sciences unsaturated soil sand resonance column bending element small strain shear modulus |
| title | Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine Sand |
| title_full | Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine Sand |
| title_fullStr | Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine Sand |
| title_full_unstemmed | Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine Sand |
| title_short | Experimental Study on Small-Strain Shear Modulus of Unsaturated Silty-Fine Sand |
| title_sort | experimental study on small strain shear modulus of unsaturated silty fine sand |
| topic | unsaturated soil sand resonance column bending element small strain shear modulus |
| url | https://www.mdpi.com/2076-3417/12/17/8743 |
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