Predicting the Strength Properties of Swelling Clay

This paper studies empirical correlation between expansive soil index properties and soil strength. Disturb soil samples from different areas in Sudan were collected to represent the most expansively soils in the country. The samples were collected from Al-Qadarif (S1), Wad Medani (S2) and Al-Giraif East in Khartoum (S3). The basic properties of the soil samples were measured. The three soils give high plasticity and very weak strength. The chemical analysis shown that S1 has the highest montmorillonite mineral than the other two soils. Therefore S1 is considered as the most expansively soil compared with the other soils. The consistency factor which was developed can be used to correlate the basic properties of the soil with the soil strength. The consistency factor is a combination of the moisture content, dry density, void ratio, liquid limit and plasticity index. These parameters are combined in a way reflecting the influence of each of them on the soil property. The strength properties (CBR and UCS) were measured for the soil samples compacted at different moisture content and different dry densities. Very good linear relationships were developed between the consistency factor and the strength properties. The correlations developed were verified by using the data of this study and the data reported by some previous researchers. The developed correlation was plotted on Nomograph