Previous studies, mostly experimental, have reported conflicting observations on the effect of the initial anisotropic consolidation stress ratio (eta 0) on the stress ratio at the onset of instability (eta f) for drained and undrained loadings that involve static liquefaction. They indicate that as eta 0 increases, eta f could decrease, increase, or remain invariant, albeit without providing potential mechanistic factors. In this study, the anisotropic critical state theory (ACST) is used to investigate potential factors, including compressibility, state, and fabric anisotropy, that can explain the influence of eta 0 on eta f under undrained and drained loading. The assessments consider numerical simulations with the ACST-based SANISAND-F model, insights from SANISANDF-based instability criteria, the instability surface concept, and available experimental observations. Our findings show that compressibility and fabric anisotropy (and its evolution) are key factors in explaining the influence of eta 0 on eta f. In particular, the results show that if fabric evolution is not substantial, an increase in eta 0 decreases eta f for materials with significant compressibility, whereas the effect of eta 0 in low compressibility materials is minimal. On the other hand, for materials that promote fabric evolution, the results suggest that the effect of fabric changes counteract compressibility effects, potentially increasing eta f. Finally, the study also highlights the need for further research to better understand potential coupled effects of compressibility and fabric evolution on materials prone to significant loading-induced fabric changes.

来源平台：CANADIAN GEOTECHNICAL JOURNAL