Coupled correlation of long-term compressibility and PCPT dissipation results in NC clays

The compressibility of clays is an important design consideration for constructions in soft clay deposits. The piezocone penetration test can be effectively used for characterizing mechanical states and depth profile of saturated clays. While various methods using piezocone penetration test results have been proposed, most of them have focused on the mobilization of the excess pore pressure and coefficient of consolidation. Little attention has been given to the assessment of compressibility. This is mainly because no volume change is measured during the penetration and dissipation process. In this study, the assessment of long-term compressibility for normally consolidated clays, as represented by the compression index, is explored. For this purpose, coupled correlation of time, volume change and stress is introduced. For verifying the methodology presented in this study, several case examples are adopted and used to compare measured and predicted results.