Lateral Pressure Distribution and Shear Band Development in Two-Tiered MSE Walls under Footing Loading

Abstract

A series of model tests were carried out to determine the effects of reinforcement type and footing location on the performance of two-tiered mechanically stabilized earth walls (T-TMSEWs) under strip loading. By preventing and allowing the footings to tilt, the influence of the degree of footing freedom was also examined as the third variable. Particle image velocimetry showed that the use of a two-tiered configuration in mechanically stabilized earth (MSE) walls and a decrease in the soil–reinforcement interaction and stiffness changed the slip surface geometry and prevented the development of deep slip surfaces in the lower tier. It was found that although the decrease in reinforcement stiffness and its interaction with soil decreased the bearing capacity of the strip footings on two-tiered MSE walls, it also reduced the lateral displacement of the T-TMSEWs under footing loading. Also, allowing the footing to tilt was found to be an effective solution for minimizing the deformation of the backfill surface and the induced lateral pressure. Moreover, comparison of the results with analytical methods showed that the construction of MSE walls in two-tiered configurations reduced the lateral pressure in the upper tier. This became more noticeable with a decrease in the soil–reinforcement interaction and reinforcement tensile stiffness and an increase in the distance from the footing to the wall crest.