Impact of lead and sodium carbonate on consolidation and hydraulic properties of clayey sand

ABSTRACT: Leakage of lead as poisonous heavy metal from pipelines, chemical storages, and industrial waste disposal is of great concern to geo-environmental engineers due to industrialization and development of suburban districts of megacities. Despite its growing environmental concerns, lead contamination can change the geotechnical properties of clayey soils, such as compressibility and hydraulic conductivity with wide application in design of foundations and buffer systems, respectively. Therefore, the main objective of this study is to explore the consolidation characteristics of different sand-bentonite mixtures contaminated with three concentrations of lead nitrate. More importantly, the influence of sodium carbonate additive as a remediation technique for the contaminated soil is investigated. Results revealed that the addition of lead nitrate caused a reduction in compressibility coefficient and a rise in consolidation coefficient. However, the sodium carbonate treatment adversely affects the two consolidation properties. On the other hand, the addition of 10% sodium carbonate reduced the hydraulic conductivity of the contaminated soil about tenfold. Form practical point of view, the studied countermeasure is not recommended for load bearing materials but recommended for enhanced isolating liners.