Abstract: With the vacuum preloading becoming an important method in soft soil treatment, improving the preloading effect within an appropriate preloading time has become particularly important. The conventional vacuum preloading methods may require a large amount of rockfill materials; Or the physical properties of the surface soil do not increase significantly, the sensitivity of the deep soil changes less, and the consolidation degree of the soil layer is average. The vacuum preloading combined with the water loading is suitable for the coastal and plain areas lacking suitable stone materials because it does not require a large amount of stacked stone materials. Throughout the application analysis of the vacuum preloading combined with the water loading in soft soil improvement, it was found that the physical properties of the shallow soil have been improved to varying degrees; The sensitivity of the deep soil layers significantly decreases, and the sensitivity of major soft soil layers is less than 2.9; The overall consolidation degree can reach over 88%. This can provide reference for the analysis of the effect of vacuum preloading combined with water-based soft foundation pretreatment under similar geological conditions in coastal areas.

Key words: Soft Soils, Surcharging, Vacuum Preloading, Combined Water Load