Abstract:Triaxial creep experiments of slates under different confining and axial pressures are done through the XTR01 electric-fluid servo-compression machine,which are taken from the West Route of South-to-North Water Transfer Project. During the creep process,decay creep and steady creep appear under different axial pressures,which can be described through the viscoelasto-plastic model. The model comprises three parts:Newton¢s model,Bingham¢s model and viscoplastic model. The constitutive equation of the model is established and the characters are analyzed. The creep parameters are fitted through the experiment data. The creep rate of the slates are also fitted. The results show that the creep rate decreases gradually until it reaches the steady rate. All these results can be used to analyze the deformation of the slates later.