LAUSR

The effect of silt content on the mechanical behavior of silt-clay transition soils under three-dimensional stress conditions is presented. Undrained true triaxial tests with constant b values were performed on normally consolidated specimens of silt-clay transition soils created from the same base clay and non-plastic silt, however, with systematically varying gradations. With increasing amount of non-plastic silt, the cohesive soils exhibit less contractive tendencies, stiffer stress-strain response and larger shear strength. The magnitude of intermediate principal stress, as indicated by the b value, also strongly influences the stress-strain relations, pore pressure behavior and both total and effective failure surfaces. Although the transition soils exhibit overall clay-like behavior, more pronounced frictional characteristics, as indicated by the shapes of the failure and plastic potential surfaces, were exhibited with increasing silt content.