Compressibility of Clays: Fundamental and Practical Aspects

Abstract
The compressibility of natural clays is influenced by numerous factors: strain rate, temperature, sampling disturbance, stress path, and some restructuring factors. The first part of the paper reviews the effects of these factors, in particular of strain rate and temperature. The influence of drainage conditions on the effective stress-strain curves followed in various subelements of a consolidating clay layer is also discussed. In a second part, in-situ conditions are considered. In the overconsolidated range, and at the preconsolidation pressure, the behavior is influenced by most of the aforementioned factors, and can be compared with laboratory test results only on the basis of a semiempirical approach. In the normally consolidated range, major factors are strain rate and temperature, and their effect can be evaluated. In some cases, however, structuring phenomena can exist and decrease the viscous effects. Finally, practical conclusions concerning the evaluation of long-term settlements are given.