investigating failure mechanism in narrow backfills under passive translation mode using piv technique

A narrow backfill is defined as a confined area located behind a retaining wall, which is constructed adjacent to an existing structure or rock face. to investigate the behavior of granular soils situated behind rigid retaining walls under passive transition conditions, three physical models were developed. the particle image velocimetry (piv) technique was employed to capture the gradual deformation occurring in the soil behind the wall, facilitating high-resolution analysis of soil movements. this advanced imaging method enabled researchers to visualize and quantify the intricate changes in soil structure as external forces were applied. the findings from the image analysis revealed that, as the wall began to move toward the soil, the initial response was compaction of the soil behind the wall. subsequently, a shear band was initiated at the toe of the wall and progressively extended toward the rock face, resulting in a nonlinear failure surface. the aim of this study is to investigate the effect of aspect ratio (the width-to-height ratio) of the backfill on the failure surface. as the aspect ratio of the backfill increases, the backfill type gradually changes from a narrow to an infinite state, and therefore the failure surface created behind the wall does not reach the rock wall but extends to the ground surface.