Abstract: The impact of highway embankment over soft soils on the entire highway construction project is obvious. Inappropriately treated soft soil might result in a series unfavorable issues that affecting the performance during the construction as well as in service life of the highway embankments. As the surcharge load in the combination of surcharge and vacuum preloading methods, the soil can also serve as part of the embankment fill and no need of significant unloading. Therefore, both the construction schedule and cost can be saved. This paper presents a case history of an expressway project. The construction monitoring results for the combined surcharge and vacuum preloading methods are compared with the estimated results. It is proved that this combination is effective for the soft soil improvement.

Key words: Surcharge Combined with Vacuum Preloading Method, Horizontal Defections, Ground Subsidence, Soil Improvement Mechanism