Evaluation of Expansive Potential of Fine Grained Soils of Tabriz Northern Highway Based on Shrinkage Limit

Shrinkage and swelling has been opposed and any soils that drying shows mark of shrinkage and cracking; is ability of swell when absorbs water. Soil swelling is reversible phenomenon. That’s mean shrinks the soil after decreasing moisture; so it is natural checked the phenomenon shrinkage, also.
Tabriz Northern Highway route is located on fine-grain soils that have been creation of clay and marl soils. This highway has a very young age but effect of geological phenomena on the various pieces of this route has caused creation longitudinal and transverse fractures and cracks, that one of the destructive phenomena is swell and shrinkage of the fine-grain soils. In this research, after local investigation, sampling has been done and by determining the shrinkage limit with using indirect and direct methods, the swelling potential of fine-grained soils of this highway has been investigated. On the samples has conducted tests of particle-size analysis, determination of limits Atterberg, and free swell. All specimens were classified as CL according to the USCS classification. Activity of samples is less than 1 and clay content is between 24 and 34 percent. Shrinkage limit between 12 to 18 percent, plasticity index between 10 to 23 percent, and free swell with use consolidation device (Oedometer) between 3 to 10 percent has been determined. Also, shrinkage limit of samples has been determined by drawing Casagrande curve based on plasticity index and liquid limit and this result was obtained that is a good accordance between free swell and tests. At last swelling potential of samples has been determined based on empirical relationships and swelling potential of soils is between low to medium.