B. Khoraminezhad - Postgraduate student
M. R. Alavi Moghaddam - Assistant professor
H. O. Bayat - Associate professor, Department of Civil and Environmental engineering, Amirkabir University of Technology, Tehran ۱۵۸۷۵-۴۴۱۳, Iran

Due to their high buffering potential and very low permeability, cohesive soils are frequently used as water-proof-elements in landfill projects. However, stabilization of such clayey barriers has been a major issue in adapting cost-effective methods to enhance soil stability. Therefore, it was deemed worth investigating the effect of Di-Ammonium Phosphate (DAP) solutions compromised the majority part of phosphorus fertilizers to improve geotechnical properties of Hamedan’s clayey landfill barrier (located in the west part of Iran). A series of contaminated specimens were prepared by mixing sampled clays with industrial DAP in concentrations ranging from 0.01 to 0.1mole/l. The conventional geotechnical experiments such as compaction, unconfined compressive strength, and direct shear box were then performed. Findings indicate that: Increasing phosphorus ion concentration in the specimens improves Cohesion (by 24%), and unconfined compressive strength (by 12%), and decrease internal friction angle (by 11.78%) and maximum dry density (by 1.5%). Accordingly it could be deduced that leaching phosphorus ion through landfill blanket has a noticeable effect on the stability of the Hamedan’s landfills.

Landfill, Geotechnical properties, Di-ammonium phosphate, Soil stabilization