Prediction of Expansion Degree for Natural Compacted Clays
This paper presents a laboratory study aimed at developing a reliable method to predict the expansion degree of clays. The work herein is intended to complement, not replace, existing research in this area. Utilizing test data for 128 natural soils, a regression analysis was performed to assess the use of the liquid limit, the plasticity index, the percent clay, the percent colloids, and activity of a soil as single variables to estimate the swell potential under a 1-psi (6.9-kPa) pressure of a specimen compacted to maximum dry unit weight based on the standard AASHTO test at optimum water content. Through multiple regression analysis, combinations of the aforementioned variables were also used to evaluate the swelling potential and to predict the degree of expansion. These relationships were used to establish nomographic charts for quantitative and qualitative evaluation of swell characteristics. The results of the proposed charts are shown to be in good agreement with swell test data provided by various researchers.