Kerman collapsible clay amendment by lime, bentonite, and nano silica

Grounds and foundations, underground structures

This paper presents an experimental study to understand the effects of selected additives on Kerman collapsible soil behavior which is dominated with such clay and is semi-arid province in the south-east of Iran. Collapsible soils, known as problematic soils, are materials with a relatively high porosity and demonstrate a potential for sudden and large decrease in their volume under water content changes with or without change in the applied stress level. In this study, soil samples are obtained from a project site in Kerman city and the collapse potential tests were performed on the prepared samples in accordance with ASTM as double oedometer consolidation test. Initially, the undisturbed level of collapsibility. Next, samples are treated with three kinds of additives namely: lime and bentonite in the 3, 5 and 8 percent and nano silica in 0.4, 0.7 and 1 percent of dry soil weight. For each percentage of additive, one sample was created and the results demonstrated that 5 % of Lime, 3 % of Bentonite and 1 % of nano silica are the optimum percentage of additives for decreasing the collapsibility. The collapsibility of Kerman clay is reduced significantly after treating with lime and nano silica in comparison to bentonite.