Influence of Swelling Clay Content on Ion Migration and Column Performance in Lime Column Treated Soils

The main purpose of this study is to investigate the effects of swelling clay mineral content on ion migration and column performance during stabilization of expansive soils by lime column technique. For the purpose of the study, soil samples which contain Na-bentonite in different percent amounts were prepared and laboratory scale models were built for each sample. Na-bentonite proportions of samples were chosen to be 0%, 20%, 40%, 60%, 80% and 100%. At the end of the curing time, migration of Ca2+ and OH- ions were determined by chemical analysis and the relations between bentonite proportion and migration distances of ions were revealed. Moreover, the changes on swelling behaviour of soil samples were determined by using experimental methods. The results of this study reveals that migration distances of Ca2+ and OH- ions reduced with increasing bentonite content. However, migration distances of ions followed a steady course after 60% of bentonite content. Ca2+ ion migrated to larger distances than OH- ions in the soils with 0%, 20%, 40% of bentonite while migration distance of the ions in soils with 60%, 80% and 100% of bentonite were the same. Additionally, the highest stabilization was detected in the soil with 100% of bentonite although the biggest migration distance was detected in the soil with 0% of bentonite. The results of this study show that the effects of swelling clay proportion in the soil on ion migration and column performance during stabilization of swelling soils with lime column technique are quite important.