In Situ Short-Term and Long-Term Rockfill Compressibility as a Function of Void Ratio and Strength of Parent Rock

This article presents a study on 15 concrete face rockfill dams (CFRDs) carried out to characterize in situ rockfill compressibility. The stress-strain-time behavior of rockfill for each CFRD was evaluated at the embankment centerline, during and after construction and before the onset of reservoir impoundment. By comparing the behavior in different case studies, the rockfill in situ compressibility parameters were defined and related to key material properties. It was shown that short-term and long-term response of rockfill to changes in stress level is a function of two parameters: the strength of individual rock particles and the void ratio of the rockfill assemblage. Moreover, the time-dependent and short-term rockfill compressibility parameters are connected. This study provides a good framework to characterize and estimate the behavior of rockfill during and after construction of embankments. Moreover, the concepts presented in this paper can be used for predicting postconstruction deformations of structures constructed by using compacted rockfill on the basis of their behavior during construction.