Variation of the Hydraulic Conductivity of Clayey Soils in Exposure to Organic Permeants

Abstract

Clayey soils are the most common material used in waterproofing and play an essential role in waste and contamination control. Permeability is a key parameter in such problems and its determination is needed in ensuring the satisfactory performance of the soil. Research has shown that a permeant fluid with a low dielectric constant can shrink the double layer around the clay particles which will, in turn, increase the permeability of the soil. In this paper, the permeability of two types of clay with different plasticity, exposed to the flow of water and methanol as polar and miscible solvents and gasoline and car oil as non-polar and immiscible solvents is investigated. In addition, the effect of soil properties such as plasticity and compaction water content on permeability of the samples is examined. To this end, soil samples are prepared and compacted at various water contents. Then, permeability tests are conducted according to the modified constant head method and the effects of parameters such as the fluid dielectric constant, water content of the samples and soil plasticity are examined. The results demonstrate that the lower dielectric constant of the organic fluid decreases the thickness of the double layer, providing more space for the flow of the permeant and as a result, the permeability of the clay increases. The reduction of the permeant dielectric constant from 80.4 to 2.28 led to a remarkable increase in soil permeability.

Effect of solid waste landfill leachate contaminants on hydraulic conductivity of landfill liners

“…The DDL model is a conceptual model developed by Helmholtz-Smoluchowski (1879-1914 and improved by Gouy-Chapman (1910)(1911)(1912)(1913) (Mortezaei & Karimpour Fard 2017). The DDL model is widely used to describe interactions between clay and liquid.…”

“…The DDL model is widely used to describe interactions between clay and liquid. The factors affecting the thickness (t) of the DDL layer can be explained by the following equation based on the Gouy-Chapman theory (Daniel & Shackelford 1968;Mortezaei & Karimpour Fard 2017).…”

“…Many researchers have reported that most organic chemicals will cause an increase in the hydraulic conductivity of clay soil (Moon et al 2007;Amadi 2013;Mosavat & Nalbantoglu 2013;Mortezaei & Karimpour Fard 2017;Wang et al 2019).…”

“…There are studies in the literature suggesting that organic liquids increase soil permeability due to their low dielectric constants (Kinsky et al 1971;Fernandez & Quigley 1985;Mosavat & Nalbantoglu 2013;Mortezaei & Karimpour Fard 2017).…”

Significance of Some Soil Amendments to Improve Plant Growth and Nutrients Uptake in Some Soils

“…The suitability extent of calcareous soils for agriculture depends on management systems via adding of organic materials and some amendments to improve availability of nutrients, particularly phosphorus and hydraulic conductivity (Karimi et al 2012). Determination of hydraulic conductivity is needed ensuring the satisfactory land use (Mortezaei and Karimpour-Fard 2017). The soil characteristics such as, texture, pore size distribution, bulk density, organic matter content, Abdeen AUJASCI, Arab Univ.…”