Geotechnical evaluation of residual granitic soils contaminated with gasoline

Abstract

Human activity brings several risks of contamination with pollutants of varying types and effects, with hydrocarbon compounds being of great concern as they are released by vehicles, industrial and construction activities and in areas with fuel reservoirs, among others. Hence, when these contaminants reach the soil, a legitimate question arises regarding their impact on the soil's resistance characteristics. This work presents a case study of granite residual soils contaminated with gasoline under 8-, 16-, and 32-days. Physical and mechanical characterization were conducted. Direct shear tests have stated high enhancement in cohesion of the samples contaminated with gasoline, exposing their lubrification effect while enveloping the particles grains. CBR and structural analysis values exposed support capacity reduction up to 16%, probably due to the gasoline´s aggressiveness as a chemical agent, altering the general structure of the soil. It seems that gasoline is a complex addition to the soil-water-air interaction, possibly transforming the soil into a hydrophobic material and thus separating the water as the connecting agent, affecting the overall structure and support capacity of the soil.