1) Replacement and cushion method. When the soft soil layer is not thick, part of the soft soil below the subgrade surface can be excavated and replaced with stable, non-corrosive cushion material such as gravel; this method is the replacement or cushion method.
2) Preloading method. This method is suitable for fill loads greater than or equal to the design load. Under the preloading load, the foundation is induced to consolidate and settle in advance to improve its strength; after the design requirements are met, the load is removed and the road pavement is constructed.
3) Dynamic compaction method. Heavy tamping or dynamic compaction is suitable for foundations with large voids and soft cohesive soil foundations with moisture content within a certain range. This method can reduce compressibility by 200% to 1000%.