Studying the effects of contamination on the geotechnical characteristics of soil is crucial to achieving sustainable development of brownfield reuse as well as to increase demand for using them. Soil that has been artificially contaminated was examined for specific geotechnical engineering properties. The effects of contaminants on the geotechnical properties of soil require careful investigation. The main aim of this study is to examine the impact of lead nitrate and cadmium nitrate contaminants on the geotechnical characteristics of clayey soil. The soil samples were selectively infused with cadmium nitrate and lead nitrate contaminants at three distinct doses (100, 300, and 500 ppm). The soil is incubated for 30 days after being treated with solutions of lead nitrate and cadmium nitrate separately. The findings showed that these contaminants had a considerable influence on the soil’s geotechnical and chemical properties. The impact of pollutants, primarily lead and cadmium, on Atterberg’s limits and geotechnical characteristics is examined in this work. While the maximum dry unit weight has a declining trend, the plasticity index reduces as both pollutants’ concentrations rise. Higher amounts of lead and cadmium result in raising optimum moisture content. Notably, the free swell index for lead shows a small incline whereas it stays constant for cadmium. Furthermore, unconfined compressive strength decreases as cadmium concentration rises same as for lead concentration grows. When lead and cadmium are present in soil, the pH of the polluted soil drops. The thickness of the diffused double layer tended to decrease and the clay particles flocculated due to the salt solutions. These results provide crucial insights into the complex behavior of polluted soils, facilitating the understanding and monitoring of their geotechnical features.