Abstract:With the large-scale exploitation and deep mining,the breaking of rock roadways under high stress becomes very serious. So,the stability of rock roadways is increasingly analysed by using the theories and methods of nonlinear sciences. In this paper,the constitutive equation of the nonlinear Kelvin¢s rheological model in uniaxial stress is derived;and the analytical solution of its creep curve is developed. Then,the nonlinear creep equation is solved by two numerical differential methods respectively. It is found that the numerical solutions of the nonlinear creep equation are different from the analytical solutions in some conditions;in other words,the numerical solutions may be instable. And by using variable substitution,the nonlinear creep equation can become of the Logistic equation. Thus,it theoretically shows that chaos occurs in the nonlinear creep deformation of rock mass;and the condition is obtained in which the chaotic behavior of rock mass happen. Therefore,based on a practical displacement time series,the theoretic basis is given to predict and to control the stability of rock mass engineering in deep ground,by using the chaotic method.