Abstract: Current evaluations of loess collapsibility within construction standards often neglect the impact of engineering-induced vibrations, leading to a significant underestimation of settlements in operational projects. This study investigated the effects of vibrations on deep loess layers(4.0~34.0m)at the Huaneng Zhengning Power Plant site in China. Undisturbed soil samples were analyzed using a modified consolidation apparatus equipped with a vibration loading device that measured the additional collapsibility coefficient under vibrations, along with the conventional self-weight collapsibility coefficient. The findings revealed that the vibrations substantially increased the loess settlement, with the ratio of self-weight-plus-vibration-induced collapsibility to self-weight collapsibility ranging from 1.1 to 2.2 across the loess strata. The total collapsibility under vibration reached 809.2mm, which was 1.6 times the self-weight collapsibility(513.6mm). These results demonstrate that the engineered vibrations significantly exacerbate settlement beyond static predictions. This study offers critical insights for re-evaluating collapsibility assessments in vibration-prone loess regions and validates an experimental method for quantifying vibration-induced collapsibility.