Shear and Elastic Moduli of Fine-Grained Soils: Impact of Consolidation Pressure and Plasticity Characteristics: Fid-Bau Portal

Shear and Elastic Moduli of Fine-Grained Soils: Impact of Consolidation Pressure and Plasticity Characteristics

Ajmera, Beena / Tiwari, Binod / Phan, Quoc-Hung (Bob)

Montmorillonite, kaolinite, and quartz were used to prepare 20 samples in the laboratory to have liquid limits ranging from 8 to 486 and plasticity indices ranging from 4 to 431. The samples were normally consolidated to pressures ranging from 25 kPa to 100 kPa and then subjected to bender element tests to determine the maximum Young’s modulus of elasticity and maximum shear modulus. Both the maximum Young’s modulus of elasticity and the maximum shear modulus were observed to depend on the consolidation pressure, the clay mineralogy, and the plasticity characteristics. In particular, an increase in the consolidation pressure would result in an increase in the modulus of elasticity and the shear modulus. At a constant plasticity index, a soil containing montmorillonite had a higher moduli value than a soil containing kaolinite. An increase in the plasticity index corresponded to a decrease in the value of the maximum Young’s modulus of elasticity and the maximum shear modulus. Little variations were observed in the values of the maximum Young’s modulus of elasticity and the maximum shear modulus when the plasticity index exceeded 250 regardless of the consolidation pressure or the clay mineralogy. Figures that can be used to estimate the maximum Young’s modulus of elasticity and the maximum shear modulus as a function of the clay mineralogy, plasticity characteristics, and consolidation pressure are provided.