Study on the Performance of Lime Column Technique for Treatment of a Na-Bentonite Clay

Abstract

Lime column technique is one of the common methods which are used in order to treat swelling soils. The improvement mechanism of lime columns is based on reactions between lime and clay as a result of ion migration from the column. In this study, the performance of lime column technique on treatment of a Na-bentonite clay was investigated. For the purpose of the study, a laboratory model study was conducted. In the model, the column diameter was chosen 50 mm and a curing time of 60 days was considered. At the end of the curing time, free swelling tests were performed on the specimens extracted from different distances to the column in order to determine the changes on swelling behaviour of the bentonite. According to test results, a treatment distance of 50 mm was achieved and an improvement of 46.36% was obtained within the distance of treatment. The results of this study show that the most appropriate soils for lime column technique are the soils which have high permeability and contain a considerable amount of tree-layered clay minerals (such as Na-smectite).