Combined Effects of Corrosion and Migration of Fines on Stability of Mechanically Stabilized Earth Walls

Mechanically stabilized earth (MSE) walls have been used extensively in transportation systems that are designed for a service life of several decades. MSE walls often include steel strips' reinforcement (typically galvanized steel strips) within granular backfill to stabilize the backfill through anchorage. In MSE walls, the reinforcement may rupture or be pulled out from granular backfill. In the current MSE wall design method, the strength and pullout resistance of reinforcements are evaluated to ensure the stability of the walls. The pullout resistance represents the reinforcement- backfill interaction. Due to environmental effects, some reinforcements deteriorate by corrosion and lose their structural capacities. Moreover, water cycles from precipitation promote migration of fines through the granular backfill. Migrating fines may accumulate in the granular backfill, clog drainage, and retain water-which in turn accelerates the corrosion process-and affect the reinforcement-backfill interaction. Therefore, corrosion and migration of fines could affect the strength and the mobilization of tension in the reinforcement. So far, limited studies have been carried out to investigate the performance and behaviors of the MSE walls when they are subjected to both corrosion and migration of fines. The focus of this parametric study is to investigate the combined effects of corrosion and migration of fines on the global stability of MSE walls. The limit equilibrium (i.e., the Bishop simplified method) in ReSSA Version 3.0 program was used to determine the potential failure surfaces in the walls and calculate their corresponding factors of safety. The combined effects were simulated by varying the properties of steel strips and reinforced fill. The results indicated that when corrosion (with a degree of 50%) was simulated, the factor of safety marginally decreased by approximately 9.5%. However, when both corrosion (with a degree of 50%) and migration of fines (with fines content of 15%) were simulated, the factor of safety decreased by approximately 13.5%.