Abstract:Aiming at the warning issue of high slopes,the changing characteristics between the slices through the shear stress relaxation of rocks and soils on the sliding surface are performed considering the inhomogeneity of geological body and the progressive evolution features of slopes,which are based on the improved Bishop slicing model. According to the friction law of a single variable,the single slice bifurcation evaluating model by combining the friction law with the simplified slicing dynamic model of the slope,which is defined by shearing stress of the sliding surface,sliding velocity and the displacement of the slope,is built up. Introducing the adiabatic approximation hypothesis from synergetics,the bifurcation model of slope displacement prognosis is constructed. By introducing the extreme condition of the velocity changing of slopes,the nonlinear evolution formulae to describe the process of unstable failure of slopes are presented;and then,the way from a single variable analysis of the systematical prognosis of slopes is proposed. Meanwhile,the chaotic dynamic evolution and early warning criterion of slopes are both put forward according to the condition of target point. By applying the prognosis model and early warning criterion to a certain high slope of Meihe expressway in China¢s Guangdong Province, the reliability of the models is testified;and the conclusion that the prognosis accuracy near tension crack points is higher than those of other locations is obtained. The achieved results can provide a new way for early warning of slope safety.