Back-to-Back Mechanically Stabilized Earth (MSE) walls have become an integral part of the transportation infrastructures, especially as ramps, bridge approaches, etc. The permeability, strength and constructability attributes of well-graded granular soils have rendered them as the most suitable fill material for MSE walls. However, the scarcity of such good materials compels the usage of locally available soil with high fine content (marginal fill) having low permeability and high plasticity characteristics, which can cause excessive wall deformation or even failure, if not adequately designed and constructed. This study focused on the assessment of overall performance of back-to-back MSE walls with a trapezoidal marginal fill zone surrounded by a near-optimal amount of select fill (i.e., hybrid-fill) as an alternative to the wall with select fill only. The behaviour of hybrid-fill wall at the end of construction and during heavy rainfall infiltration were investigated through finite element modelling and compared with fully select fill and fully marginal fill walls. The study revealed that the overall performance (i.e., horizontal and vertical deformations, reinforcement tension, and factor of safety) of the hybrid-fill wall with 30-47% select fill is much better than that of fully marginal fill wall, especially during the extreme rainfall infiltration scenario. The response of this hybrid configuration is even comparable with that of fully select fill wall, suggesting the proposed hybrid-fill wall as a stable as well as cost-efficient alternative system in locations where sufficient quantity of well-graded soil is not readily available.

背靠背机械稳定土（MSE）墙已成为运输基础设施不可或缺的一部分，尤其是在坡道，桥梁进近等地方。良好分级的颗粒状土壤的渗透性，强度和可施工性使其成为最重要的部分适用于MSE墙的填充材料。然而，这种优质材料的缺乏迫使使用具有低渗透性和高可塑性特征的，具有高细含量（边缘填充）的本地可用土壤，如果设计和建造不当，则可能导致墙体过度变形甚至破坏。这项研究着重于评估梯形边际填充区被几乎最佳量的选择填充物包围的背对背MSE墙的整体性能（即，混合填充）作为仅使用选定填充的墙的替代。通过有限元建模研究了混合填充墙在施工结束时和大雨入渗过程中的行为，并与完全选择填充墙和完全边缘填充墙进行了比较。研究表明，选择填充率为30％至47％的混合填充墙的整体性能（即，水平和垂直变形，增强张力和安全系数）要比完全边缘填充墙的整体性能好得多，尤其是在施工过程中。极端降雨入渗情况。这种混合配置的响应甚至可以与完全选择的填充墙相媲美，