PSI - Issue 78

Alessia Furiosi et al. / Procedia Structural Integrity 78 (2026) 753–760

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loading direction, the structure behavior is more sensitive to the backfill modeling strategy, as the transverse loading induces significant interaction between the backfill and the spandrel walls. Furthermore, a comparison between SUB-R and SUB-V reveals distinct damage patterns within the backfill itself. While both models exhibit backfill block separation, the damage in SUB-V is more distributed and irregular due to the nature of the Voronoi tessellation, whereas SUB-R shows more localized and directional failure paths. Differently, for SUB-D model, where the backfill is represented as a single continuum block, the internal damage is more difficult to visualize directly. Although stress concentrations and deformation zones can be inferred, this representation does not explicitly capture fracture patterns, limiting the interpretation of backfill failure modes.

Fig. 7. Numerical damage and collapse mechanisms and shear–displacement relationships for SUB-R, SUB-D, and SUB-V models.

The shear force–displacement relationships obtained from all three numerical models exhibit comparable load bearing capacity, indicating consistent structural behavior across the three backfill modeling strategies. The shear force was computed as the resultant of all contact forces acting in the loading direction, including contributions from