Enhancing Geotechnical Properties of Ahvaz Fine Soil with Biochar: A Preliminary Study for Landfill Cover Systems

Document Type : Research Article

Authors

Department of Civil Engineering, Faculty of Civil Engineering and Architecture, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

Abstract

The final cover of a landfill is crucial for preventing rainwater infiltration, snowmelt, and greenhouse gas emissions while complying with regulatory standards. Effective landfill covers can be made from various materials, including modified clay, to enhance soil properties. This study investigates the effects of biochar on enhancing the geotechnical properties of fine soil in Ahvaz for potential use in landfill cover systems. Different biochar percentages (7%, 12%, and 20%) were analyzed for their impact on key soil properties, including residual shear strength, permeability, unconfined compressive strength (UCS), swelling index, and compaction characteristics. The results show that the addition of biochar improves the shear strength, with the most significant increase observed at 12% biochar (70% improvement compared to untreated soil). However, beyond this percentage, the strength improvement rate declines. Furthermore, higher biochar content increases permeability and reduces UCS. The study identifies 7% biochar as the optimal content, providing a balance between strength enhancement and minimizing negative effects on other soil properties such as permeability and compressibility. This study demonstrates that biochar can be a valuable additive for landfill cover systems, though careful consideration of its concentration is essential to avoid compromising hydraulic performance. These findings provide valuable insights for geotechnical engineering applications, particularly in regions with similar soil conditions to Ahvaz.

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Main Subjects


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