Abstract: The potential differential settlement between the proposed and the existing embankment is an important issued that needs to be resolved in the highway widening projects. Column supported embankment receives more and more wide application in effectively minimize the differential settlement between the proposed and the existing embankments.  This paper introduces the components of the column supported embankments: reinforced soil; column/pile; and load transfer mat. The interactions mechanism among the reinforced soils, columns/piles and load transfer mat are discussed and the principles as well as the column supported embankment for the highway widening are proposed. As a case history, the column supported embankment is used in the soft soil improvement in Guangsan Expressway Project. The potential differential settlement between the existing and the proposed embankments is successfully minimized.

Key words: Expressway, Column Supported Embankment, Highway Widening, Soil Improvement, Differential Settlement