Stress-strain behavior of heavy metal-contaminated sand-clay mixtures stabilized with carbonate
Publish place: The 5th National Geotechnical Conference and the 2nd International Conference on Earthquake Engineering and Seismic Geotechnics
Publish Year: 1402
نوع سند: مقاله کنفرانسی
زبان: English
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شناسه ملی سند علمی:
GEOTEC05_074
تاریخ نمایه سازی: 5 شهریور 1403
Abstract:
The leakage of heavy metals from pipelines, chemical storage, and industrial waste in response to industrialization and suburban development is a significant environmental concern. These heavy metals can profoundly impact the geotechnical properties of clayey soils, notably shear strength and soil microstructure, which play a crucial role in the design of landfills and buffer liners. Due to the susceptibility of clay liners to shrinkage cracks, compacted sand-clay mixtures (SCM) are preferred in landfills. Thus, this research aims to investigate the unconfined compressive strength characteristics of various SCM contaminated with three lead concentrations (۰.۱, ۰.۲, ۰.۵ mol/l). Three types of clay including bentonite, kaolinite, and zeolite were used to study the shear behavior of SCM for liners. Additionally, the impact of sodium carbonate additives as a remediation technique for the contaminated soil was assessed. Results indicate that sodium carbonate enhances the shear strength of heavy metal-contaminated sand-kaolinite mixtures (SKM), while it reduces the shear strength of contaminated sand-bentonite mixtures (SBM). The differential behavior of SKM and SBM is attributed to the respective changes in diffuse double layers. Despite bentonite having a larger specific surface area, the primary characteristic of sand-kaolinite-bentonite mixtures (SKBM) is governed by bentonite. Consequently, the addition of sodium carbonate to contaminated SKBM results in a slight reduction in peak axial stress. Furthermore, although the compressive strength of contaminated SKM is significantly reduced with the introduction of ۵% zeolite, the incorporation of sodium carbonate in the mixture restores its strength. From a practical standpoint, while carbonate treatment improves the performance of buffer liners against heavy metal contamination, the remediated soil may not be suitable for load-bearing purposes.
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Authors
Ashkan Hosseinzadeh Namadi
M.Sc., Department of Civil Engineering, Imam Khomeini International University
Amin Hasani Motlagh
Ph.D. student, Department of Civil Engineering, University of Calgary
Pouya Alipanahi
M.Sc., Department of Civil Engineering, Sharif University of Technology
Mahmoud Hassanlourad
Associate professor, Department of Civil Engineering, Imam Khomeini International University