Abstract
The paper presents the results of experimental laboratory investigation of cohesive soils from the Warsaw area, polluted with diesel fuel. The study revealed adverse changes in key physical parameters, sorption capacity and mechanical properties. The results were analysed in relation to pollution degree as well as structural modifications. The obtained findings were further used in numerical analyses to evaluate bearing capacity, foundation settlement, and slope stability, as well as to assess the overall behaviour of contaminated soils serving as building foundations.