Effect of Vibration Cycles Batches on Shear Modulus and Damping of Dry Sand

Resonant column tests were conducted to examine the variation in shear modulus (G) and damping ratio (D) of dry sand subjected to 10 batches of vibration cycles. Each batch increment comprised 1,000 cycles. Tests were performed by varying void ratio, confining pressures, and input driving voltage. The vibration cycles cause a continuous increment in shear strain, which eventually leads to a decrease in shear modulus and an increase in damping ratio without affecting the basic variation of shear modulus and damping ratio with shear strain. The effect of each subsequent batch of 1,000 cycles reduces continuously as compared to the previous batch increment. The effect becomes more appreciable for (1) lower confining pressure and (2) greater void ratio and high input driving voltage.