The Research of an Impact in Strength Characteristics of Oil-contaminated Sandy Soils

A review of existing studies by domestic and foreign authors on changes in the angle of internal friction of sandy soils contaminated with oil products is provided. The main experimentally confirmed results of studies of the angle of internal friction of sandy soils interacting with oil products are outlined. Laboratory tests were conducted to determine the strength characteristics of sandy soils contaminated with oil products using the in-plane shear method. Coarse, medium and fine sands contaminated with A-95 gasoline, diesel fuel, and heavy oil at a concentration of 0-12% by dry soil weight were used as test samples. A methodology for conducting laboratory tests using the in-plane shear method for sands contaminated with oil products is described and tested. The degree of influence of viscosity and oil product concentration factors on the value of the angle of internal friction of sands of different sizes was determined and mathematically substantiated using regression multifactorial analysis. The sensitivity analysis of the adopted regression equation with six degrees of freedom is performed. The scope of application of the proposed function is designated. It is shown that the use of polynomials of the second kind in linear regressions leads to a significant complication of the model associated with the impossibility of explicitly identifying individual influence coefficients without additional calculation of partial derivatives to compile the function gradient with its subsequent analysis. A decrease in the angle of internal friction of coarse, medium and fine sandy soils regardless of the type of oil product and its concentration has been laboratory confirmed. A graph of the dependence of the angle of internal friction of sands of different sizes on the concentration of oil products is presented. It has been statistically substantiated that the greatest influence on the angle of internal friction of sandy soils contaminated with oil products is exerted by concentration, to a lesser extent - the type (viscosity) of oil products