Numerical Analysis of Hybrid Back-To-Back MSE Wall with Select and Marginal Backfill

Abstract

AbstractBack-to-back mechanically stabilized earth (MSE) walls are extensively used in transportation development projects worldwide due to their effectiveness, ease of construction, and cost efficiency. As per Federal Highway Administration (FHWA) guidelines, such MSE walls are to be backfilled with high-quality select fill in both reinforced and retained zones. However, considering the scarcity of high-quality fill and increased cost associated with the procurement of such material, the Indian Roads Congress (IRC) has recommended the use of inferior soil (ϕ ≥ 25° and PI ≤ 20%) in specific configuration in the retained zone for six lane projects. The present study investigates the deformation response and global stability of back-to-back MSE wall due to the inclusion of marginal soil fill in the central region of the wall. Numerical analysis using finite element software PLAXIS 2D was carried out by varying the size of marginal fill zone to investigate their effect on the behavior of wall. Specifically, the analysis was performed by varying the quality and relative dimensions of marginal soil zone to examine their effect on factor of safety and horizontal and vertical deformations. The results indicated that the quality and height of retained soil has minimal influence on global safety factor and horizontal deformation when the marginal fill is within the retained zone. However, notable increase in deformation and decrease in safety factor were observed for base width beyond 2.2H. Also, differential surface settlement of hybrid wall was found to be less than that of conventional MSE wall.KeywordsBack-to-back MSE wallsReinforced fillMarginal fillNumerical analysisSoil deformation