Volume 14, No. 4, 2020
Received: 2020/09/29, Accepted:
Authors:
Mahdi O. Karkush; Alaa D. Al-Murshedi; Hussein H. Karim;
Abstract:
Problematic soils, such as gypseous soils, have complex and irregular behavior, and are concentrated mainly in the dry and semi-dry regions in the world. In Iraq, gypseous soils cover from 30% to 35% of its total area in the west desert and extend to the southern parts of Iraq. Such soils experience sudden collapse upon wetting. Soil stabilization is an important technique to improve the undesired geotechnical properties of soils. In this study, laboratory tests were conducted on two gypseous soils collected from two different sites in Iraq: Al-Najaf city (42% gypsum content) and Al-Samawa city (54% gypsum content). Three percentages (1, 2 and 4%) of nano-clay (NC) were used to improve the chemical and geotechnical properties of the studied soils. Chemical and physical classification tests were performed on the treated soil samples. Also, collapsibility and shear
strength tests were conducted on the soil samples in dry and soaking conditions. The test results indicated that mixing nano-clay with gypseous soils affected the consolidation behavior and hydraulic conductivity of the soils regardless of the percentage of nano-clay. The collapse potential of soil samples mixed with 4% of nanoclay
decreased by 77%. In general, using 4% of nano-clay gives the best improvement of chemical and geotechnical properties of gypseous soils.
Keywords:
Nano-clay, Gypseous soil, Collapse, Shear strength, Soaking