Vacuum preloading

as a widely adopted ground improvement method for saturated soft soils with high water content

is extensively applied in large-scale coastal reclamation projects. However

post-reinforcement bearing capacity remains insufficient in many engineering cases

particularly with limited strength improvement in deep soil layers. Numerous studies have demonstrated that the consolidation efficiency of vacuum preloading is constrained by two critical factors: depth-dependent attenuation of vacuum pressure and fine particle enrichment-induced clogging of drainage paths near prefabricated vertical drains. To address these challenges

this study integrates electro-osmosis with vacuum preloading (EVP) during the later stage of vacuum preloading in the dredger fill project of Yueqing Bay North Port Area. A large-scale model test pool was employed

where conventional vacuum preloading was conducted for 108 days until settlement stabilization

followed by a two-phase EVP intervention. The first phase lasted 11 days

after which electrode polarity was reversed for the second phase (6.5 days)

totaling 17.5 days of EVP reinforcement. Post-EVP results revealed significant improvements: at depths of 20 cm

60 cm

and 100 cm

soil water content decreased by 4.2%

4.84%

and 2.34%

respectively

while vane shear strength increased by 32%

75%

and 61.1%. The test results indicate that superimposing the electro-osmosis method during the later stage of vacuum preloading can achieve a significant improvement in vane shear strength (with a water content reduction of less than 5%). Particularly for deep soil layers with low initial strength that are difficult to reinforce solely by vacuum preloading

the strength increased by 61%−75%

demonstrating effective reinforcement performance.