Prediction of Stable Displacement and Unstable Time on Tunnel and Slope

In this paper, according to features displacement-time curves the possibility to use acceleration as a factor of state identification is suggested and testified. In the stable cases, the prediction of the ultimate convergence displacements by means of GM（1, 1 ） model of grey system is discussed.In the unstable circumstances,the general formula of calculating unstable time with tangent angle is established.