Abstract：By analyzing the mechanical characteristics of prestressed bearing of the slope body，the stability of prestressed anchored slope should be calculated according to coupling and decoupling between slope body and anchors，respectively. The characteristics and the composing of the anchoring forces in decoupling moment are studied. The long-term observations are developed on a practical slope engineering reinforced by prestressed-cable frame；and the tension forces in the cables and earth pressure along the beam bottoms are synchronistically measured，which are founded in existence of the decoupling between slope body and anchors. The practical slope engineering lies in the Yuanjiang—Mohei Expressway of Yunnan Province，China. In fact，the value of the anchoring force in decoupling moment has a close harmonic connection with the displacement of the unstable mass along the underlying weaker plane. The conclusion can be drawn from the theoretical analysis and the long-term observations that the anchoring force in decoupling moment is made up of the residual prestressed force and the shearing resistance between soil and grouting. On the assumption that the slope body is homogeneous and that the prestressing anchored slope is a plane strain system considering the groundwater，secondary forces and the bending of the anchor cables，the calculation method of the slope stability in decoupling moment is then advanced on the basis of the displacements of the soil along the potential sliding surface. The proposed calculation method can consider the actually working conditions of the anchor cables and the slope body，so it has the advantages against existing methods；and the result achieved from the new method is more reasonable. A case study proves the feasibility of the new method.
