STATISTICAL EVALUATION OF EMPIRICAL CORRELATIONS FOR THE COMPRESSION INDEX (CC) IN BRAZILIAN SOFT SOILS

Resumo

One-dimensional laboratory consolidation test is used to discover one of the most important
parameters of consolidation of cohesive soils, the compression index (Cc). However, it is a long test
and requires the utmost care to obtain reliable samples. Geotechnical correlations are largely used
because it can give fast means of parameter prediction using simple tests. These correlations are
constructed from local data and need to be evaluated before used in other regions. This paper reports
on laboratory tests conducted in soft soils of Brazil and shows a more complete form of statistical
evaluation for the correlation of the Cc. The database is formed by 430 results of Cc and moisture
content (wn) collected in the national literature. The correlations analyzed are exclusively in function
of wn. The equations were evaluated using 17 statistical tools for each of the 11 compression index
correlations. Comparison between the results showed the best correlations and the less suitable
correlations for the database in this study. In this paper an attempt has been made to present the
empirical correlations proposed by various researchers for compression index in function of moisture
content. The results will be useful in identifying empirical equations to estimate the compression index
of Brazilian soft soils.