Compression and Strength Characteristics of Two Silts of Low and High Plasticity

Abstract

The potential for enhanced strength or stiffness arising from the microstructure of natural silty soils compared with their reconstituted state is examined using the framework for clays, to assess the extent to which it can be used for silts. A detailed study performed on two clayey silts of low and high plasticity, respectively, in their intact and reconstituted state, is used to illustrate the different response of the silts compared with clays in terms of compressibility and strength, e.g., multiplicity and shape of the normal compression lines and strong dilative tendencies during undrained and drained shearing. This paper shows that the response of the reconstituted silts can be used as a reference to identify the influence of the microstructure on the compressibility and strength of the intact silts. The results are found to give clear signs of structure in both compression and shearing only for the low-plasticity silt. Stiffness measurements corroborate these findings.