Optimizing gypseous soils permeability utilizing clayey soils, both treated and untreated

Abstract The main problem of gypseous soils is the solubility. These soils possess essential engineering characteristics and remain durable when dry. However, saturation due to rainy weather or increased water table will lead to drains out of the content minerals. Such a case makes buildings erected upon such soils are susceptible to collapse. This study investigates the suitability of clayey soils for improving gypseous soil. Two soil samples, designated as Soil I (gypsum concentration: 35.4%) and Soil II (gypsum content: 12.3%), were collected from Al Najaf City, Iraq, and subjected to laboratory testing. This study explores the use of inexpensive, locally available clayey soil to improve the engineering properties of gypseous soils, thereby mitigating the negative effects of wetting. The testing program included measurements of soil permeability, total dissolved solids (TDS) content, and electrical conductivity (EC). The testing procedure used to assess the impact of soil treatment with varying clayey soil content on permeability characteristics, tests were conducted on both treated and untreated soil samples. Leaching procedure applied on the samples for 5 days to examine changes in the parameters. Initial test results revealed variations in data collected from the tested soils. However, these variations progressively diminished, suggesting that clayey soil is a viable material for modifying the inherent permeability of gypseous soils. As testing continued, the data converged towards constant values.