Abstract: In order to study the deformation features of the in-pit dumping site of Yuanbaoshan Surface Mine,based on the control and calculation on the deformation of the bulky soil as the main object,a rheological test was applied to determine the numerical calculation parameters and the Burgers creep model was applied to the analysis on a settlement law of the dumping site in the backfill process and after the backfill completed.And in the vertical direction,a slicing treatment was conducted on the in-pit dumping site.With the dumping height increased,under the dynamic load role of the top overburden,each slicing all would have settlements occurred.With the establishment of the Burgers creep model suitable to the in-pit dumping site,the settlement,displacement and late settlement law in the filling process were analyzed.The calculation results showed that in the rolling area,a max late settlement was 30.7 cm and the horizontal displacement was 27.3 cm.At the year end of 2020,a river channel would be constructed and would meet the deformation requirement of the river.At the non rolling area,the max late settlement was 2.74 m and the horizontal displacement was 2.12 m.The dumping operation of the in-pit dumping site would be completed after 2.5 years and the soil deformation and settlement would be basically completed.