Geotechnical Evaluation of Diesel Contaminated Clayey Soil

Abstract

Soil contamination by different hydrocarbons has rapidly expanded worldwide, surpassing the self-purification capacity of soils and increasing the number of contaminated sites. Although much effort has been devoted to study the effects of diesel contamination on the geotechnical properties of soil, there is still limited available information about it. Moreover, there is no available information about the maximum diesel retention that soil can have and its effect on the geotechnical behavior of the soil. Thus, in this paper, we determined the maximum diesel retention by an unsaturated clayey soil and evaluated the impact of diesel contamination on its geotechnical properties. The results showed that the soil could only retain 12.6% of the added diesel and the excess was expulsed. At such a diesel concentration, the saturation rate of the soil was lower than 80%. Diesel contamination increased the plasticity and the internal friction angle of the soil, while its cohesion was considerably decreased. It should be noted that the matric suction of contaminated soil was lower than the one obtained for natural soil. However, its osmotic suction was considerably higher. This indicates that osmotic suction must be considered to evaluate the shear strength of contaminated soils.

Evaluation of the Soil–Water Retention Curve of Arsenic-Contaminated Soil by the Filter Paper Method

“…Then, the contaminated soils were manually mixed and stored in hermetically sealed glass containers in the temperature-controlled room (20 • C ± 1 • C) during a curing period of six weeks. The contamination procedure and the curing period were applied to simulate the long-term contamination effect on the soil [10]. After this curing period, the porosimetry and the specific surface area of the soil were analyzed by nitrogen adsorption-desorption isotherms to evaluate the changes promoted by arsenic contamination.…”

“…Frequently, the first zone of the soil that gets contaminated is the unsaturated zone [10]. The unsaturated condition of the soil involves the treatment of stress variables that depend on capillary (attributed to interactions generated from surface tension phenomenon) [11] and adsorption forces that generate negative pressures on the soil.…”

“…Most of the problems that involve unsaturated soils are commonly the result of environmental changes, which can cause the expansion or reduction of the soil volume. Those changes affect the matric (ψ m ) component of the soil suction and cause the osmotic suction (ψ o ) to become essential in the shear strength of the soil when chemical contamination arises [10]. The soil's total suction (ψ t ) corresponds to the sum of the ψ m and the ψ o .…”

“…In contrast, it has been proposed that under contaminated conditions, the ψ o becomes relevant due to the reactions between the soil and the contaminant, which modifies its geotechnical properties and, consequently, the shear strength resistance of the contaminated soil [10]. Moreover, the water flow is affected by the void spaces between solid particles because changes in water content result in changes in the soil's suction [14].…”

Controlled diesel-mixed soils for roadway embankments: laboratory and ultrasonic characterization

“…Safehian et al (2018) mixed illite clay with diesel to improve the overall soil compressibility. Hernández-Mendoza et al (2021) studied the effect of diesel on clay and detected enhancements on its mechanical behavior. Table 1 presents a summary of results from the literature.…”