Static simple shear characteristics of Nak-dong River clean sand

Embankments established on the Nak-dong River are composed of sandy soils which are not compactible. In this paper, undrained and drained static simple shear tests were conducted on air pluviated and water pluviated Nak-dong River clean sand at the loosest deposited state and at other deposition void ratios over a range of confining stress levels. In the undrained response, densification associated with the increasing confining stress level has a clear dominating influence on increasing shear stress and pore water pressure. As the void ratio decreases, small contractive behaviour gradually changes into dilative behavior. Dilative sand becomes even more dilative with a further decrease in the void ratio. The water pluviated specimen is more contractive (strain softening) than the air pluviated specimen. The air pluviated specimen did not exhibit contractive behaviour. In the drained response, in regard to incremental elastic approximation, such stress-strain results can be most often simulated by hyperbolas. Clearly, densification associated with increasing confining stress levels has a dominating influence on increasing shear stress and volumetric strain. This becomes less contractive as the confining stress increases.