Modelling and Analysis of Back-to-Back Mechanically Stabilized Earth Walls under High-Speed Train Dynamic Loading

Back-to-back mechanically stabilized earth (BBMSE) walls are used to retain soil in approach sections of highway and railway bridges having limited width of way. In the current study, a finite element-based numerical model is used to study the response of a 6 m high and 8.4 m wide connected BBMSE wall subjected to dynamic train loading. Firstly, the finite element model developed in the present study is verified with the published literature, and the proposed model is found to be in good agreement with the results provided in the literature. A detailed parametric study is conducted considering a typical dynamic loading due to a high-speed train (i.e., the Japanese E-5 series Shinkansen train). The variations in terms of the mobilized lateral earth pressure, lateral displacement of the facia, and mobilized tension and strains in the reinforcement layers with respect to the depth of the wall are studied. Additionally, the vertical settlement observed on top of the wall is studied. Furthermore, the influence of the friction angle of backfill, reinforcement stiffness, and train speed on the mobilization of lateral earth pressures and displacements along the wall, and tensile forces and strains in reinforcements at different levels are considered. It is observed that train speed and reinforcement stiffness are the two most significant parameters influencing the observed lateral earth pressure and displacement of the BBMSE wall.