Petroleum products influence the engineering behaviour of the soil. Neogene clays and glacial tills from Central Poland were tested under laboratory conditions to evaluate the changes of selected physical and mechanical parameters: particle size distribution, particle density, swelling, shear strength and permeability. Four petroleum products were used in the experiments: diesel fuel, kerosene, jet fuel and mineral engine oil. The study revealed that even for the lowest degree of contamination the values of physical and mechanical properties of the soils changed significantly. Greater variation can be expected in soils contaminated with high-viscosity compounds. Also, higher relative changes were found for glacial tills than for Neogene clays. Consolidation tests revealed changes in soil permeability depending on the soil composition and the physical properties of the contaminant – considerable reduction of permeability was observed for glacial tills contaminated with light Jet fuel, while the reduction was lower for Neogene clays. The obtained results indicate the role of mesopores and the dimensionless pore pressure coefficient in changes of soil permeability. The methodological issues regarding testing and analysing the hydrocarbon-contaminated soils were also presented and discussed, which might be useful for researchers studying contaminated soils.
Pomiar wielkości cząstek za pomocą dyfrakcji laserowej (LDA) jest alternatywną analiz hydrometrycznych (HM) metodą oznaczania składu granulometrycznego gruntów. Przy oznaczaniu frakcji najdrobniejszych, o znacznej zawartości minerałów ilastych, zasadnicze problemy wynikają ze znacznej anizotropii kształtu cząstek. W pracy zawarto porównanie wyników oznaczeń wielkości cząstek iłów neogeńskich z Bydgoszczy. Zaproponowano formuły służące do transformacji wyników metody areometrycznej i metody dyfrakcji laserowej dla badanych gruntów.
EN
Laser diffraction particle sizing is an alternative method to determine grain size analysis in soils. However, for particle with high shape anisotropy LDA measurements usually produce different results than traditional hydrometric methods (HM), based on Stokes equation. The article contains the results of analyzes of Neogene clays characterized by significant lithological differentiation in regard to participation the clay fraction particles. The research was conducted for the clay samples taken in Bydgoszcz. A set of equations to transform LDM results to hydrometric results was proposed.
The NMR technique is widely used in polymer, chemical, and agrifood industries, as well as in many other fields of science and technology. This work presents results from the use of FID (Free Induction Decay) application to determine the water content in clay soil samples. The widely used oven-drying method is time-consuming and precludes using the same sample to another test, because drying process damages the internal structure of soil. Three clay soils, characterized by high surface area, were used in the research and six to eight samples for each soil were tested. The obtained dependence curve between FID Signal Intensities and mass of water was characterized by a high correlation coefficient (R2 = 0.97). The curve can be used to determine the mass of water present in clay soil sample on the basis of FID Signal Intensity. Such approach allows 1H-NMR relaxometry to be applied for the determination of water content in soil samples in a fast and non-destructive way.
This paper discusses two different approaches to microanalysis of the soil medium. It presents testing results collected by electromicroscopy, which requires special sample preparation, and a non-destructive method, requiring no sample preparation and using a computer-assisted tomograph. The paper presents: • Applicability of microstructure analyses and chemical microanalysis in the determination of structural damage incurred in the historical time in relation to the effect of contemporary abiotic events; • Application of a standard medical computer-assisted tomograph in qualitative assessment of structure and observations of mechanisms of failure in the cement/peat soil composite. Investigations concerning the applicability of computed tomography in soil micromechanics are demonstrative in character and the presented conclusions suggest further directions for research.
The objective of this study was to investigate the influence of oil pollution on geological-engineering properties of clay soils. Presented results prove that the difference in physical-chemical characteristics of water and oil substances results in unfavourable changes in geological-engineering parameters of the ground soil. Laboratory tests show that the range of change depends on the soil type and the pollutant content. Contaminated area should be then carefully examined when evaluated in the aspect of land development.
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