Soil Water Retention-Based Methodology for the Classification of Expansive Soils

Determination of swell potential is important for geotechnical and geo-environmental designs involving expansive soils. A new soil water retention based methodology is proposed for qualitatively classifying the swell potential of soils. The method is based on the expansibility coefficient (EC) of soils which quantifies the hysteric behavior of specific moisture capacity curve due to the crystalline swelling. The criteria for classification of soil expansibility based on EC index are established by calibrating measurements with other existing methods. Swell potentials of a suite of soil samples ranging from non-expansive to expansive are characterized using different methods for comparison. The EC results show that the proposed methodology can capture the effect of different factors on swell potential, particularly the type of exchangeable cation.