Centrifuge model study on the influence of PVD installation depth under surcharge preloading

To investigate the effect of PVD installation depth on the efficiency of surcharge preloading for soft ground improvement, centrifuge model tests were conducted based on a typical airport runway project. Four test groups were designed with PVD installation depths of 18, 22, 26, and 30 m. Key indicators, including settlement, pore-water pressure, water content, and undrained shear strength, were monitored to systematically analyze the influence of PVD depth variation on soil consolidation behavior. The results showed that with each 4 m increase in PVD depth, the settlement increment was 10.39 %, 4.44 %, and 0.81 %, respectively. When the installation depth exceeded 22 m, the improvement effect tended to plateau. Therefore, under the conditions of this project, the reasonable installation depth of PVDs lies within the range of 18–22 m, while the precise optimal depth still requires further investigation. Based on one-dimensional and multidimensional consolidation theories, this study proposed a settlement prediction method that converts multi-stage surcharge into an equivalent single-stage load through stress-time integration correction. The predicted results agreed well with the experimental data, with errors in shallow and deep settlement controlled within 5.3 % and 11.6 %, respectively, both within the acceptable range for engineering applications. • Simulating surcharge loading by varying centrifuge acceleration. • Determine the optimal depth range for vertical drain installation. • Proposed a load-time integral correction method. • High-accuracy settlement prediction by converting multi-stage loading to single-stage.