Triaxial compression rheological experiments on carbonaceous slate specimens of deep buried tunnel were carried out on the rock rheology testing machine. Along with the increase of loading stress level and the improvement of moisture conditions, the initial attenuation creep phase, the stabilization creep phase, and the speedup creep phase were produced. By connecting Burgers model and the nonlinear viscoplastic body consisted of nonlinear viscous component η(n,t) parallel connected with the plastic component in series, the improved model could describe the speedup creep phase. Using this model to fit and analyze the rheological parameters of different moisture conditions, it is shown that η〖KG0.005mm〗 M、E M、E K and η〖KG0.005mm〗 Kwill decrease with negative exponential trend. Then water damage D(w) was introduced, and through deriving damage evolution equation, the nonlinear viscoelasticplastic model with water damage effect was established. Finally, the time effect deformation of surrounding rock under different times and different moisture conditions was studied by numerical simulation, and the results show that primary support should close in 168 h, and the best construction time for secondary lining is 360 h after the primary support is closed.