FE Analysis of Back-to-Back Mechanically Stabilized Earth Walls Under Cyclic Harmonic Loading

Back-to-back mechanically stabilized earth walls (BBMSEW) are encountered in bridge approaches, ramp ways, rockfall protection systems, earthen dams, levees and noise barriers. However, available literature studies and design guidelines for BBMSEW are limited and not supported by the numerical modeling when back-to-back walls perform interaction. Under static condition, the distance between two opposing walls is a key parameter used for determining the analysis methods of BBMSEW in the Federal Highway Administration Guidelines. Moreover, existing design methodologies do not provide a clear and justified answer how the required tensile strength of reinforcement and the external stability change with respect to the distance of the back-to-back walls under seismic conditions. For this purpose, an attempt has been made, in this paper, to analyze the performance of BBMSEW under earthquake loading conditions using a geotechnical finite element code, PLAXIS 2D. The main focus of this research is to investigate the effect of the reduction of the distance between the opposing walls on internal and external stability of BBMSEW under harmonic cyclic loading. Parametric studies were carried out by varying the distance, associated with different BBMSEW width to height ratio, to investigate its effects on the behavior of interacted walls. The effect of the height of walls was separately presented. By keeping the distance between walls as constant, the influences of the peak ground acceleration and frequency of the harmonic cyclic loading were also investigated. The results were evaluated in terms of horizontal walls displacements and the tensile loads on the reinforcement layers. © 2017, Indian Geotechnical Society.