Abstract：Based on the project of high-embankment widening of highway，the water content and degree of compaction of foundation soil，filling and improved soil by lime were determined by means of indoor physico- mechanical test. The centrifugal modeling tests were used to simulate increasing degree of compaction and improve soil by lime for coordinating deformation between new and old high-embankment widening. The test results show that the deformation of high-embankment widening was decreased，but differential settlement was not controlled effectively when the degree of compaction of high-embankment widening was increased to 93%，94% and 96% from 90%，93% and 95% correspondingly. Then both deformation of high-embankment widening and differential settlement were decreased when the filling was improved by 6% lime mixture；and the effects of deformation compatibility of high-embankment widening were enhanced. The in-situ monitoring data agree well with the results of centrifugal modeling test.
