Abstract：Considering effects of weakness of rock parameters，a creep damage constitutive model with variable parameters is proposed. In the model，the creep parameters of the rock are weakened with time gradually，so the deterioration process of the material can be reflected by unsteady creep parameters directly. The central difference equation in three-dimensional condition of creep damage constitutive model is deduced. The constitutive model is programmed by the secondary development of software FLAC3D using C++ and FISH. The model is applied in slope project of dam foundation at Dagangshan Hydropower Station. Based on the results of the compressive creep test，the creep damage parameters of rock mass in dam site are inversed. Reasonable evaluation and suggestions for the slope design and construction are provided though three-dimensional calculation of creep damage stability of the slope excavation at Dagangshan Hydropower Station.
