Effect of rail axle load on geosynthetic reinforced back-to-back mechanically stabilized earth walls: Experimental and numerical studies

Abstract

Back-to-back Mechanically Stabilized Earth (BBMSE) walls are generally used in approach embankments of flyovers and bridges. The complex geometry of two interactive MSE walls in a single structure makes it a special case for the study. This paper presents the performance evaluation of unconnected, connected and overlapped geogrid reinforced back-to-back mechanically stabilized earth walls supporting the railway tracks at bridge approaches. Scaled model tests were conducted to study the behaviour of BBMSE walls. Overburden (OB) waste generated from coal mining was used as the sustainable backfill. 3D Finite Element analysis was carried out to validate the model test. A parametric study was also carried out on varying W/H ratio, overlapping length, connected and unconnected geogrid reinforcement, geogrid stiffness and spacing. Train bogie load with its eight-point load was used as a loading condition. Lateral, vertical deformations of walls, geogrid strain, maximum tensile force developed in the geogrid for all the cases were investigated and discussed in detail. Geogrid arrangements were found to be critical in reducing the wall displacement. The overlapping length of the geogrid resulted in lesser deformation with the deformation reduction of 58 % compared to the connected geogrid.