Evaluation of compression index of marine fine-grained soils by the use of index tests

Marine fine-grained soils are well known for their compressibility, which is typically measured and reported in terms of compression index, C-c. The difficulties associated with measuring C-c have resulted in growing research interest in statistics-based estimates (i.e., correlation equations). Although many empirical and semiempirical correlations exist for estimating C-c, most available correlations are based on either data from nonmarine soils or data collected from Japanese and Korean marine clays. Thus, there are few correlations for marine clays from other parts of the world. In the present study, two independent databases which contain a total of 1,000 data points from 170 different sites worldwide are used to build and validate statistically significant correlations for estimating compression index of marine soils. The results of this study suggest that (1) the proposed correlation equations provide quite good estimates of C-c for marine soils with different stress histories and sensitivities and (2) most of the existing models have unacceptable performance when they are applied to marine soils.