Estimating the amount of swelling potential of clay soils with high plastic properties

Expansive soils are considered among problematic soil groups and the predication of the expansion rate of these soils is important. In the present study, three types of different clay soils with different specifications have been randomly selected from three different areas of some countries. The samples pertaining to the first series have been selected from Indonesia, in which montmorillonite is the mixed soil of most of constituent minerals and enjoys an extremely high expansion potential (between 70 to 122 percent). The samples of the second series are related to a city in northern Oman. This type of soil has a very high plastic property. The percentage of montmorillonite in this soil is higher than that of the other minerals available in this soil. The samples of the third soil in this study are the result of research on compacted soils in which the samples have mainly consisted of a combination of silica sand with kaolinite and bentonite clays of different percentages. In the present study, those soils have been used that fall within the category of fine-grained soils as per the unified categorization. In this study, regression analysis was used by means of Design-Expert software for different values of plastic properties in the samples under study in order to estimate the expansibility of the soils with high plastic properties. Comparing the relationship obtained in this study and that of Seed et al., the correlation coefficient in this study is higher. This suggests the high and proper precision of the relationship.