Abstract: Plenty of high-fill slopes need to be strengthened in engineering projects in the mountainous area of the northwestern district of China with complex geological conditions. To provide sufficient anchoring force to fill slopes and to ensure their stabilities, we put forward a new structure of safety, stability, economy and convenience, named frame with prestressed anchor-plates, which suits for reinforcing the slopes with large fill, and whose reinforcement effect is great. Based on the limit equilibrium theory, we proposed the formula for pull-out resistance and the checking calculation method for the stability. Finite element analysis software PLAXIS 3D was applied to compare and verify the results of the proposed method. The displacement of the slope and the internal forces of a column in the frame are further analysed, which explains the rationality of the results of numerical simulation, and proves that the frame with prestressed anchor-plates is effective for strengthening the slope and limiting the displacement by comparing with the displacement data of a slope project. By analysing the variation of axial force and frictional strength during the process of construction, the working mechanism between the plates and the soil is exposed, and the influence of the prestress on the structure is explored. The analysis results guide the design of high-fill slopes strengthened by the frame with prestressed anchor-plates.

Key words: high-fill slope, ultimate pull-out resistance, stability, a new supporting and retaining structure, PLAXIS 3D