Compressibility of Finnish sensitive clay

Tampere University of Technology (TUT) and Finnish Transport Agency (FTA) have been conducting an extensive field and laboratory experimental program aiming to evaluate the strength and deformation properties of Finnish sensitive clay. This paper presents a detailed investigation of the compressibility parameters with particular emphasis on the empirical correlations with the index properties. The traditional method used to describe the compressibility of natural clay is based on the compressibility indices (e.g., Cc, Cr) which are determined by means of 1-D consolidation tests. However, this method is not suitable to describe the compressibility of sensitive clays due to the nonlinear stress-strain behaviour beyond the preconsolidation stress ('p) shown in the semilogarithmic scale. For this reason, an alternative method for evaluating the soil compressibility based on a power law equation is presented. These methods are compared and empirical correlations between the compressibility parameters and soil index properties are established.