English：

In order to study the settlement and deformation characteristics of super-high fill subgrade ofexpressway in mountainous area, this paper relies on the super-high fill subgrade project of a expresswayin Hunan Province, formulates the monitoring scheme for super-high fill subgrade and carries out themonitoring work. Finally, the displacement and settlement of subgrade slope are analyzed. Based on themeasured settlement data of subgrade, the exponential curve is used to predict the later settlement curve,and the pavement paving time is inferred according to the settlement prediction curve. The results showthat the number of measuring points with cumulative displacement less than 4mm accounts for 54.17% ofthe total, only a few measuring points have large displacement and the overall displacement of the slope issmall. There is a certain settlement at each measuring point of the subgrade, but the overall change trendis basically same, and the final settlement gradually tends to be gentle, indicating that the subgradesettlement is stable ; The exponential curve can better fit the settlement data and predict the latersettlement trend,which can be used as a preliminary basis for the determination of pavement pavingtime.