Experimental Investigations of the Mechanical and Microscopic Behavior of Phenol-Contaminated Clay Soil

Phenol is a widely used industrial organic compound that poses significant environmental risks when released into soil. This study investigates the influence of phenol contamination on the geotechnical and microstructural behavior of low-plasticity clay. A series of laboratory tests were conducted, including Atterberg limits, standard Proctor compaction, unconfined compressive strength (UCS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and leaching test (TCLP). The results indicated that phenol contamination increases the liquid and plastic limits while slightly reducing the plasticity index, suggesting higher water retention and modified consistency. Compaction test results showed a decrease in maximum dry unit weight and an increase in optimum moisture content. UCS tests revealed a strength reduction of nearly ۷۰% in phenol-contaminated samples compared to natural soil, mainly due to decreased interparticle friction and altered soil structure. SEM images confirmed the transformation of the soil fabric from aggregated face-to-face arrangements in natural clay to flocculated and oriented structures in contaminated samples. XRD analysis identified kaolinite and montmorillonite as the primary clay minerals. Leaching tests showed that ۵۸.۵% of phenol was released, while ۴۱.۵% remained bound to the soil, indicating strong soil-contaminant interactions. Overall, phenol significantly alters the engineering behavior of clay soils, highlighting the importance of careful assessment in contaminated site management and geotechnical design.

کلیدواژه ها:

Soil interaction ، Phenol contamination ، Soil Microstructure ، Organic pollutant ، Clay mineral