In the Loess Hilly Region of China

there are numerous casualties and property losses caused by the instability of high fill slope every year.Therefore

the significance of this study is to reduce the instability of high fill slope from its fillings.Taking a high filling slope in Shaanxi Province as an example

this paper takes the gravel filling of high filling slope as the main research control object.The physical and mechanical parameters and permeability of the gravel filling are determined through many laboratory tests

and the stability of the slope is calculated by numerical simulation using FLAC 3 D.First the optimal soil-rock ratio is determined

and then the optimal gradation under the optimal soil-rock ratio is obtained.Compared with previous fillings

the filling with a selected gradation has better mechanical properties

higher strength

and better water-proof performance

and

hence

the overall stability of the slope will be strengthened.With selected fillings

the instability of slope caused by unreasonable backfill materials can be effectively reduced.