NUMERICAL ANALYSIS OF SLOPE STABILITY AND SETTLEMENT OF LOCAL ROAD EMBANKMENT CONSTRUCTED WITH CLAY AND MUNICIPAL SOLID WASTE

Abstract

The significant accumulation of Municipal Solid Waste (MSW) in Pakistan, coupled with inadequate handling and disposal practices, poses substantial health and environmental risks, creating an urgent need for sustainable utilization methods in civil engineering. The primary objective was to determine the optimal proportion of MSW (ranging from 5% to 25%) that could replace clay without compromising the stability and settlement of the shallow foundation. Numerical analysis was conducted using the advanced finite element software PLAXIS 2D. Three embankment scenarios were modeled: Case 1 (clay only), Case 2 (uniform clay-MSW mix), and Case 3 (alternate layers of clay (0.3m) and clay-MSW mix (0.7m)). A standard AASHTO single axle design load of 61 KN/m was applied to all models. The results indicate that both MSW content and the pattern of layer placement influence the slope stability and settlement response. The optimal percentage of MSW replacement was calculated to be between 15% and 20%. Specifically, replacing clay with 15% MSW in Case 2 yielded a Factor of Safety (FOS) of 1.26, and using 20% MSW in the alternate layers of Case 3 yielded an FOS of 1.28. Since these FOS values exceed the permissible limit of 1.25, the findings confirm that safe embankments can be constructed by integrating MSW with clay, offering a practical solution for the safe disposal and utilization of MSW by municipalities.