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Dynamic parameters of saturated and unsaturated sand at different ranges of shear strain levels in cyclic simple shear tests

Jafarzadeh, F ; Sharif University of Technology | 2011

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  1. Type of Document: Article
  2. Publisher: 2011
  3. Abstract:
  4. In order to evaluate dynamic properties of Babolsar and Toyoura sands at saturation levels of 25, 50, 75 & 100%, a series of cyclic simple shear tests were carried out. The SGI type cyclic simple shear device was used to study the shear modulus, G, and damping ratio, D, of the above mentioned sands at cyclic shear strain of 0.5, 5 & 10%. The effect of degree of saturation (S), vertical consolidation stress (σ vc) and number of loading cycles (N) were investigated. On the basis of the tests results, the shear modulus approximately remains constant by change of degree of saturation from 25 to 50% and decreases when reaches the degree of saturation 75%. Damping ratio approximately is constant over the range of saturation degree from 25 to 75% except for 4 samples with S=75% for which damping ratio decreases under cyclic shear strain of 10%. Due to the samples liquefaction in higher cyclic loading, the shear modulus and damping ratio drastically decreases and increases by approaching to saturated state; respectively. The results show that for a given γ, G and D increases and decreases with σ vc; respectively
  5. Keywords:
  6. Consolidation stress ; Cyclic loadings ; Cyclic shear strain ; Cyclic simple shear ; Damping ratio ; Degree of saturations ; Dynamic parameters ; Dynamic property ; Loading cycles ; Saturated state ; Saturation degree ; Saturation levels ; Strain levels ; Toyoura sand ; Unsaturated sand ; Damping ; Elastic moduli ; Geotechnical engineering ; Loading ; Soil mechanics ; Stress analysis ; Supersaturation ; Shear strain
  7. Source: 14th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering ; 2011