Improved Granite Residual Soils from a Study on Diesel Contamination in East Hunan Province

Abstract

Soil can be amended with cement, lime, fly ash and other curing agents after diesel contamination. In this study, a diesel-contaminated granite residual soil with an oil content of 9% was selected and amended with cement, lime and fly ash as curing agents and their incorporation levels were varied. A straight shear test showed that 6% lime resulted in the best improvement in the contaminated soil, with a cohesive force of 122.1 kPa and an internal friction angle of 27.1°. A disintegration test revealed that the disintegration resistance of the contaminated soil was improved by 6% cement, 20% fly ash and 10% lime, with 10% lime being the most effective. SEM tests revealed that diesel fuel acted as a constant pore fluid to cause significant fragmentation and separation of the granite residual soil from flakes and blocks to smaller agglomerates and fragments. The curing agent, by increasing the physical reaction products, causes the particles to agglomerate, filling the soil pores and enhancing the integrity of the soil, thus improving the soil properties.