A General Overview on the Correlation of Compression Index of Clays with Some Geotechnical Index Properties

The compression index \(~C_{c}\), is one of the key properties of fine-grained soils. Several correlations exist in the literature linking this parameter to other geotechnical properties such as Atterberg limits, void ratio and porosity. This paper analyzes more than 300 data from the literature plotting \(C_{c}\) against liquid limit, \(LL\), plasticity index, \(PI\), shrinkage index, \(SI\), defined as the difference between liquid limit, \(LL\), and the shrinkage limit, \(SL\), plasticity ratio, \(R_{p}\), initial porosity, \(n_{0}\). Key words for the literature review analysis were “clays”, “compression index”, “liquid limit”, “plastic limit”, “plasticity index”, “shrinkage index”, “remolded”, “undisturbed” and “correlations”. The \(C_{c}\)–\(LL\) relationships are considered taking into account the gradient, \(a\), and intercept, \(b\), of the said relationship and plotting several values of the literature to assess their origin. A new relationship between \(b\) and \(a\), called Compression Liquid Limit was obtained. Besides, an overview regarding the undisturbed and remolded compression index, \(C_{c}\), as well as the correlation of predicted versus experimental \(C_{c}\) values based on two available methods, i.e. the method of Park and Koumoto (J Geotech Geoenviron Eng 130(2):223–226, 2004) and the method of Sharma and Bora (Indian Geotech J 45:225–230, 2015. https://​doi.​org/​10.​1007/​s40098-014-0128-0) is also presented. As a result, the Park and Koumoto (2004) method is capable of predicting approximately with the precision of 1/1.5 to 1.5 the measured compression index using the initial porosity of soil sample, irrespective of the disturbance state of the soil, soil types and clay minerals.