Analysis of soil shrinkage data

A precise mathematical formula for, and accurate curve-fitting of, shrinkage data are prerequisites for the evaluation of an array of structural properties as functions of the water content (moisture ratio) of non-rigid (swelling) soils. Such a formula is used here, together with its first (slope) and second (curvature) derivatives. The structural property that is of particular interest in this paper is the “shrinkage limit”, which occurs at the water content where the curvature of the shrinkage line (dry side) reaches its maximum value. Using a set of experimental data, found in the literature, it is shown here, that beyond the shrinkage limit (on the dry side), a secondary shrinkage process may be initiated, leading to a second (lower) shrinkage limit that would not usually be noticed.