关键词: 岩石蠕变, 非牛顿黏壶, 修正的Kelvin模型, 加速蠕变

Abstract: Generally, curves of rock creep include three stages: attenuation creep stage, steady creep stage and accelerated creep stage. The traditional models for rock creep, which always contain Newtonian dashpot rather than non-Newtonian dashpot, couldn’t describe accelerated creep stage. An improved constitutive model for rock creep is proposed; and the method can be divided into three steps. First, traditional Kelvin model is not quantitatively good in description of initial attenuation creep stage and steady state creep stage. A modified Kelvin model using non-Newtonian dashpot is used here in. The power-law creep function is obtained by solving the constitutive relation. Second, the parallel connection of non-Newtonian dashpot and plastomer, whose creep function is power function, is used for description of accelerated creep. Third, by connecting instantaneous elasticity Hooke body, modified Kelvin and nonlinear viscoplastic body in series, a new visco-elastoplastic constitutive relation of rock is proposed. This creep model can describe attenuation creep stage, steady-state creep stage and accelerated creep stage. It is shown that creep testing curves under different conditions are coincident well with the theoretic curves; and the model is reasonable and feasible.

Key words: rock creep, non-Newtonian dashpot, modified Kelvin model, accelerated creep