Effect Of Overburden Pressure, Mineralogical Composition, And Plasticity On The Cyclic Behavior Of Fine-Grained Soils

A parametric study was performed to understand the behavior under cyclic loading of natural soils having different mineralogical composition and depositional environments. Soil samples were collected from seven different locations including 2015 Gorkha Earthquake affected area in Nepal and the Portuguese Bend Landslide in southern California. Those soil samples were subjected to monotonic and cyclic simple shear tests at various testing conditions. Cyclic strength curves, stress-strain hysteresis, and shear modulus reduction curves were developed for all of the tested soil samples. The results demonstrated an increase in the cyclic strength with increases in the plasticity index. The cyclic strength was also found to depend upon the mineralogical composition of the soil mass. Highest relative cyclic strengths were observed at consolidation pressures of 50 kPa with little differences in the relative cyclic strengths between consolidation pressures of 100 and 800 kPa. The relative stiffness of the soil mass was seen to increase with an increase in the consolidation pressure.