Volcanic Cohesive Soil Behaviour under Static and Cyclic Loading

The objective of this study is to evaluate the behavior of reconstituted (disturbed) samples of volcanic soil under static and cyclic loading using a series of undrained static and cyclic tests. The static test results show that under low confining pressure, the disturbed sample is contracted and then dilated with no sign of temporary liquefaction. On the contrary, the undisturbed sample is dilated under low confining pressure and becomes contracted when reaching the peak of the soil strength. However, under high confining pressure, both disturbed and undisturbed samples show a contraction. The cyclic test results show cyclic mobility behavior under an investigated cyclic stress ratio. At a low cyclic stress ratio, the shear strain increases slowly, and after a certain number of cycles, the shear strain significantly increases. Conversely, the shear strain increases gradually at a high cyclic stress ratio. These results indicate a contradictive behavior of the soil under different confining stress and cyclic stress ratios. © 2021 Southeast Asian Geotechnical Society. All rights reserved.