Effect of Material Composition on Geotechnical Properties—Study on Synthetic Municipal Solid Waste

The geotechnical properties of municipal solid waste (MSW) are required to design and maintain a landfill structure. Several landfill failures occurring in recent times have led to the loss of revenue and people. This study aims to investigate the impact of material composition on the geotechnical properties of fresh synthetic municipal solid waste (SMSW), which imitates the real waste produced in India. The study aims to understand the contribution of each material, such as paper, plastic, and organic matter, on the shear behavior of SMSW, which is essential for designing landfills and ensuring their safety and performance. A modified proctor test and a large-scale direct shear test were used to determine the unit weight and shear strength of SMSW, respectively. The synthetic waste’s unit weight and shear strength were found to be consistent with values that had already been published. The shear strength parameters of SMSW include cohesion, which was determined to be at the lower bound of the envelope, and friction angle within the envelope. Lower unit weight, less fine soil-like material, and dry material are thought to be the causes of the observed variation in the behavior of actual waste in synthetic waste. The findings of this experiment demonstrated that as the proportion of paper increases, the cohesion (C) increases, and the friction angle (Φ) decreases. Cohesion and friction angle both decrease as the proportion of plastic increases. Cohesion and friction angle both increase with an increase in the organic percentage. These findings demonstrate that each material contributes differently to the shear behavior of SMSW. Hence, the material composition’s effect should be considered while designing a landfill for improved safety and reliability.