Performance Assessment of a Landfill Expansion Stabilized with Reinforced Fill Structure Using Numerical Analysis

This study investigates the feasibility of landfill expansion using the limit equilibrium and finite element methods. A 15.5 m high reinforced fill structure (RFS) was analyzed to assess how fill type, consolidation rate, geometric configuration, waste strength, compaction and the inclusion of banquettes affect horizontal displacement, differential settlement, reinforcement strain and facing behavior. The baseline configuration demonstrated acceptable settlement, reinforcement strain, and gabion performance but exceeded allowable horizontal displacement limits. The scenarios including increasing consolidation rate and substitution with sand fill further aggravated displacements, whereas banquettes significantly reduced lateral movement and settlement, demonstrating their effectiveness in stabilizing slopes. Enhancing the industrial waste properties decreased displacements substantially improving overall stability. Geometric modifications, such as widening the reinforced zone, enhanced displacement control, while higher compaction achieved the best global performance, albeit with increased gabion compressibility. Extending geogrid length provided only marginal improvements beyond a certain threshold. Overall, banquettes, enhanced waste properties, and improved compaction were identified as the most effective strategies for stable efficient landfill expansion, emphasizing the importance of displacement control and reinforcement–facing interaction.