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Evaluation of the effects of principal stress direction on shear modulus of unsaturated sand using hollow cylinder apparatus

Jafarzadeh, F ; Sharif University of Technology | 2019

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  1. Type of Document: Article
  2. Publisher: CRC Press/Balkema , 2019
  3. Abstract:
  4. Determination of soil shear modulus is one of the most controversial topics in unsaturated soil dynamics. Due to the fact that soils have an anisotropic response, the shear strength and stiffness of geological materials are greatly dependent on the principal stress direction and the intermediate principal stress. In this study, the effects of principal stress direction on shear modulus of unsaturated medium-dense sand have been investigated using cyclic hollow cylinder apparatus. Three series of stress-controlled cyclic tests with different fixed principal stress directions were carried out on the sand sample under different values of suction. Results reveal that shear modulus of unsaturated sand is strongly affected by the principal stress direction (α). From α = 15° to 45°, shear modulus decreases independently of the suction level, but from α = 45° to 75° the trend of shear modulus versus α is dependent on the suction value. As a result, the increase of matric suction not only increases the shear modulus of sand but also changes the effect of principal stress direction on shear modulus of unsaturated sand
  5. Keywords:
  6. Cylinders (shapes) ; Earthquakes ; Elastic moduli ; Geotechnical engineering ; Sand ; Shear strain ; Shear strength ; Soil mechanics ; Soils ; Anisotropic response ; Controversial topics ; Geological materials ; Hollow cylinder apparatus ; Intermediate principal stress ; Strength and stiffness ; Unsaturated sand ; Unsaturated soil ; Shear flow
  7. Source: 7th International Conference on Earthquake Geotechnical Engineering, ICEGE 2019, 17 January 2019 through 20 January 2019 ; Pages 3102-3108 , 2019 ; 9780367143282 (ISBN)