Numerical Analysis of MSE Walls with Sustainable Backfills Using Limit Equilibrium and Finite Element Method

This study compared the global stability of Mechanically Stabilized Earth walls with sustainable backfills using the Limit Equilibrium Method (LEM) and Finite Element Method (FEM). A total of 120 models were analyzed, examining backfill type (sand, recycled concrete aggregate, and reclaimed asphalt pavement), reinforcement type, wall height (2–8 m), length-to-height ratio, and retained slope angle. Recycled concrete aggregate provided comparable stability to sand (FS ≥ 1.5), while reclaimed asphalt pavement often failed minimum requirements in walls over 6 m or with steep slopes. In LEM analyses, geogrids provided higher factors of safety, achieving up to 6.6% improvement in critical conditions. FEM results showed geogrids reduced lateral displacements and earth pressures by 5–6% compared to geotextiles. Both methods showed strong agreement (FS difference < 5%), with FEM identifying failure surfaces initiating at the reinforced zone’s rear. All designs met serviceability limits, with horizontal displacements remaining below 0.21% of wall height. Foundation pressures remained below theoretical values due to soil arching. Recycled concrete aggregate was viable for walls up to 6 m, while reclaimed asphalt pavement required geometric modifications. For taller walls or steep slopes, extended reinforcement (length-to-height ratio > 1.0) and hybrid stabilization were recommended.