EXPERIMENTAL STUDY ON THE DYNAMIC SHEAR MODULUS AND DAMPING RATIO OF SATURATED SAND UNDER CYCLIC LOADING

  • Jian Zhang Nanjing Vocational Institute of Transport Technology, Nanjing 211188
  • Jiuting Cao Jiangsu Zhongshe Group Co., Ltd., Wuxi 214072, China
  • Sijie Huang Tianjin Research Institute for Water Transport Engineering, Tianjin 300456, China
  • Baocun Shi Hohai University, Nanjing 210098, China
Keywords: initial shear stress, saturated sand, dynamic shear modulus, damping ratio

Abstract

Initial shear stress is inevitable in actual engineering slopes, subgrades and foundations, and soils exhibit different dynamic characteristics under the influence of initial shear stress. Using a dynamic triaxial test system, this study explores the dynamic shear modulus and damping ratio of saturated sand from Wenchuan, investigates the effects of the initial shear stress and vibration frequencies on the dynamic shear modulus and damping ratio of saturated sand and proposes a normalised dynamic shear modulus formula that considers the initial shear stress and vibration frequency. Results show a threshold dynamic shear strain of the saturated sand. When the dynamic shear strain is below this threshold, the dynamic shear modulus significantly increases with the initial shear stress and vibration frequency. Otherwise, the influence of the initial shear stress and vibration frequency gradually decreases and eventually stabilises. The initial shear stress significantly affects the normalised dynamic shear modulus/strain curves where a larger initial shear stress corresponds to a higher curve. Meanwhile, the vibration frequency only exerts a slight influence. The curves under different frequencies are generally within the same band and fall near the Seed upper envelope. The initial shear stress also has a significant influence on the damping ratio where a larger initial shear stress corresponds to a smaller damping ratio. On the basis of the experimental results, a normalised dynamic shear modulus/shear strain formula that considers the influence of the initial shear stress and vibration frequency is established. Fitting results indicate that this formula shows good agreement with the test data.

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Published
2021-09-30
How to Cite
1.
Zhang J, Cao J, Huang S, Shi B. EXPERIMENTAL STUDY ON THE DYNAMIC SHEAR MODULUS AND DAMPING RATIO OF SATURATED SAND UNDER CYCLIC LOADING. MatTech [Internet]. 2021Sep.30 [cited 2021Nov.28];55(5):741–749. Available from: https://mater-tehnol.si/index.php/MatTech/article/view/230