The vacuum preloading method is used to consolidate the supersoft ground of an expressway. The test indicated that the improvement effect is very obvious. Compared with the conventional preloading method
the project construction time can be decreased by a quarter; the settlement of roadbed reduces 1/3. The strength of soil increases by 1.5 times. The consolidation degree of soil is larger than 95 % after the embankment of height of 6.2 m was filled and vacuum preloading was constructed for 3 months. The displacement of foundation soil is smaller than 0.2 mm/d during the construction period; the embankment and ground soil are stable. The predicted settlement is less than 20 cm. The experience can also be used in similar engineering.