Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions range
Collapsible soils, such as loess, are classified as problematic soils and are usually stable in unsaturated conditions in nature. However, when they are exposed to a moisture increase, especially under an applied load, they undergo a sudden decrease in volume or collapse. Various aspects of the beha...
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Sharif University of Technology
2024-09-01
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| Series: | مهندسی عمران شریف |
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| Online Access: | https://sjce.journals.sharif.edu/article_23396_c20980078b5b09cfbf0eb38b48969b6e.pdf |
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| author | S. Mohsen Haeri B. Sadollahzadeh s. soleymani borujerdi |
| author_facet | S. Mohsen Haeri B. Sadollahzadeh s. soleymani borujerdi |
| author_sort | S. Mohsen Haeri |
| collection | DOAJ |
| description | Collapsible soils, such as loess, are classified as problematic soils and are usually stable in unsaturated conditions in nature. However, when they are exposed to a moisture increase, especially under an applied load, they undergo a sudden decrease in volume or collapse. Various aspects of the behavior of unsaturated collapsible soils including volume change, soil-water retention, and shear strength have been extensively investigated so far. However, few studies have been carried out on the effect of initial shear stress on the hydromechanical behavior of unsaturated collapsible soils. This study aims to investigate the effect of initial shear stress on the hydromechanical behavior of Gorgan loessial soil under isotropic and anisotropic triaxial compression in the medium suctions including 300 and 400 kPa using a fully automated unsaturated triaxial device. In this study, a set of stress-controlled triaxial tests were performed on reconstituted specimens of Gorgan loessial soil implementing a “suction decrease under constant mean net stress” hydromechanical stress path. The tests were conducted in medium-range suctions under different initial shear stresses. Strain-controlled triaxial shear tests were also conducted at the end of isotropic and anisotropic compression, to evaluate the shear behavior of the tested specimens. Results taken from the wetting stage indicate that the volume reduction of the specimens increases with an increase in initial shear stress under constant mean net stress. The results obtained from shear tests on specimens with constant matric suction and mean net stress in the wetting stage show that the greater the initial shear stress, the lower the shear strength of the specimen. Also, according to the independent stress variables approach, the shear resistance parameters including c´, ϕ´, and ϕb have been obtained at 4.7 kPa, 32.9°, and 13.6°, respectively. In addition, regression lines through the steady-state data points, used to define the CSL of the reconstituted specimens, had an M-value of 1.19. |
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| institution | Kabale University |
| issn | 2676-4768 2676-4776 |
| language | fas |
| publishDate | 2024-09-01 |
| publisher | Sharif University of Technology |
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| series | مهندسی عمران شریف |
| spelling | doaj-art-51c5e8dd38d34752b50c509fdf1e2e2c2024-11-13T06:32:22ZfasSharif University of Technologyمهندسی عمران شریف2676-47682676-47762024-09-0140210111110.24200/j30.2023.62479.322823396Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions rangeS. Mohsen Haeri0B. Sadollahzadeh1s. soleymani borujerdi2Dept. of Civil Engineering Sharif University of TechnologyDept. of Civil Engineering Sharif University of TechnologyDept. of Civil Engineering Sharif University of TechnologyCollapsible soils, such as loess, are classified as problematic soils and are usually stable in unsaturated conditions in nature. However, when they are exposed to a moisture increase, especially under an applied load, they undergo a sudden decrease in volume or collapse. Various aspects of the behavior of unsaturated collapsible soils including volume change, soil-water retention, and shear strength have been extensively investigated so far. However, few studies have been carried out on the effect of initial shear stress on the hydromechanical behavior of unsaturated collapsible soils. This study aims to investigate the effect of initial shear stress on the hydromechanical behavior of Gorgan loessial soil under isotropic and anisotropic triaxial compression in the medium suctions including 300 and 400 kPa using a fully automated unsaturated triaxial device. In this study, a set of stress-controlled triaxial tests were performed on reconstituted specimens of Gorgan loessial soil implementing a “suction decrease under constant mean net stress” hydromechanical stress path. The tests were conducted in medium-range suctions under different initial shear stresses. Strain-controlled triaxial shear tests were also conducted at the end of isotropic and anisotropic compression, to evaluate the shear behavior of the tested specimens. Results taken from the wetting stage indicate that the volume reduction of the specimens increases with an increase in initial shear stress under constant mean net stress. The results obtained from shear tests on specimens with constant matric suction and mean net stress in the wetting stage show that the greater the initial shear stress, the lower the shear strength of the specimen. Also, according to the independent stress variables approach, the shear resistance parameters including c´, ϕ´, and ϕb have been obtained at 4.7 kPa, 32.9°, and 13.6°, respectively. In addition, regression lines through the steady-state data points, used to define the CSL of the reconstituted specimens, had an M-value of 1.19.https://sjce.journals.sharif.edu/article_23396_c20980078b5b09cfbf0eb38b48969b6e.pdfloessial soilhydromechanical behaviorinitial shear stressreconstituted specimenunsaturated triaxial device |
| spellingShingle | S. Mohsen Haeri B. Sadollahzadeh s. soleymani borujerdi Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions range مهندسی عمران شریف loessial soil hydromechanical behavior initial shear stress reconstituted specimen unsaturated triaxial device |
| title | Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions range |
| title_full | Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions range |
| title_fullStr | Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions range |
| title_full_unstemmed | Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions range |
| title_short | Assessment of unsaturated behavior of Gorgan loessial soil under anisotropic triaxial compression in medium suctions range |
| title_sort | assessment of unsaturated behavior of gorgan loessial soil under anisotropic triaxial compression in medium suctions range |
| topic | loessial soil hydromechanical behavior initial shear stress reconstituted specimen unsaturated triaxial device |
| url | https://sjce.journals.sharif.edu/article_23396_c20980078b5b09cfbf0eb38b48969b6e.pdf |
| work_keys_str_mv | AT smohsenhaeri assessmentofunsaturatedbehaviorofgorganloessialsoilunderanisotropictriaxialcompressioninmediumsuctionsrange AT bsadollahzadeh assessmentofunsaturatedbehaviorofgorganloessialsoilunderanisotropictriaxialcompressioninmediumsuctionsrange AT ssoleymaniborujerdi assessmentofunsaturatedbehaviorofgorganloessialsoilunderanisotropictriaxialcompressioninmediumsuctionsrange |