Cyclic Strength of Stratified Soil Samples

Abstract

This paper presents the results of a laboratory testing program on the influence of stratification on cyclic strength of soil samples. Reference undrained cyclic triaxial tests were conducted on fine Ottawa sand samples and a much finer silica silt sample. Both samples were prepared by pluviation under water. Undrained cyclic triaxial tests conducted on stratified sand-silt samples revealed that layering induced a much lower cyclic resistance than that developed in either of the materials. Differential pore pressure generation in each soil unit suggest that water migration occurred from the sand layer to the silt layer and caused this strength reduction. The experimental data have significant implication for field conditions, especially for submarine slopes.