Effect of Adding Lime to the Consolidation Properties of Clay - Gypsum Soils

Maroon irrigation and drainage network is located in the south east of Khuzestan province of Iran where the most regions the soils are chalky. In this research, the very specimens were gathered in the destroyed canal locations of existing irrigation network. Then, the various engineering tests were performed to determine of the physical, chemical and mechanical properties of the soil samples. The results showed that often destruction have occurred due to poor geotechnical condition of embankment such as swelling and dissolving of gypsum soils. In this research, the lime was used to rehabilitation of problematic soils which the content of lime in per cubic meter was 50, 100 and 200 kg. The consolidation tests were performed in order to investigate of mechanical properties of clay–gypsum soils. Findings showed that all contents have a significantly effect on decreasing the rate of soil consolidation. So that the calculations showed that at the maximum and minimum cases, the consolidation coefficient decreases to 50 and 4 times for 100 kg content of lime respectively. Moreover, findings showed that the 50% time of consolidation in the first loading, increases to 26 times rather that natural soil of zone for 50 and 100 kg content of lime. In addition, the results showed that the compression index 180 times decreased for 50 kg content of lime. While, the swelling index in rehabilitated samples were smaller than the natural soils also. For 50 kg content of lime, this index decreased to about 7 times.