Wpływ zanieczyszczenia olejem napędowym na zmianę uziarnienia, plastyczności i pęcznienia neogeńskich osadów zastoiskowych z rejonu Dobre

Petroleum products are hazardous to the natural environment, as well as to the stability of underground infrastructure and foundations. Numerous studies have reported negative changes in the geological and engineering parameters of soil contaminated with hydrocarbons. In Poland, the impact of pollution with petroleum hydrocarbons on the physical and mechanical properties of soils is still poorly understood and requires studies considering soil lithology, duration of the pollution and the type of pollutant. The soil tested in this study was Neogene limnic soil, collected in the Dobre area, composed of 12.5% clay, 46.5% silt, 41% sand, and kaolinite as the dominant clay mineral. Soil samples containing 0%, 2%, and 6% of diesel fuel (ON) were prepared in laboratory to simulate long-term contamination. With the increase in ON content, the clay content decreased by approximately 4% points, resulting in a classification change from loam (G) to sandy silt (Rp) for the 6% ON sample. Greater differences in particle size distribution were observed using the hydrometer method compared to the micro aggregate method. Compared to the 0% ON sample, contaminated samples showed an increase in the values of Atterberg limits, plasticity index, consistency index and activity. This changes align with literature data for soils of kaolinitic and illitic composition. Consistent with its lithological composition, the tested soil showed low values of the sorption and swelling parameters, indicating low potential expansivity. Although there was a slight increase in the MBC sorption capacity, cation exchange capacity and specific surface area, the contaminated soil samples revealed lower values of free swelling and higher values of swelling pressures compared to the uncontaminated soil. However, the macroscopic observation of samples after the free swelling test and the reduction in the adsorbed water content after the swelling pressure test point to the conclusion that due to the presence of hydrocarbons in the soil structure, its potential for sorption capacity and volume changes was reduced. This research demonstrates that even a relatively low level of soil contamination with petroleum-derived compounds resulted in a change in its geological and engineering properties. Due to the limited data, the presented conclusions require further research applying higher degree of soil contamination. It was also shown that a careful and comprehensive analysis of test results is necessary for the proper interpretation/assessment of the results of standard tests but conducted for non-standard soil material, where the pore liquid consists of water and hydrocarbons.

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Opracowanie rekordu ze środków MNiSW, umowa nr POPUL/SP/0154/2024/02 w ramach programu "Społeczna odpowiedzialność nauki II" - moduł: Popularyzacja nauki (2025).