Creep mechanical model of rock mass with weak structural plane

In view of the simulation defects of existing research in mechanical creep model of rock mass in the accelerated creep stage, based on the Kachanov-Rabotnov creep damage theory, a nonlinear element was developed, and a nonlinear viscoelastoplastic creep model composed of six elements by connecting the developed element and the Burgers creep model in series was formed to realize the accelerated creep stage simulation of rock mass containing weak structural plane. The results show that, according to the established model, if accelerated creep does not occur, the creep deformation is the multiplication of steady state creep rate and time; if accelerated creep occurs, the material constant λ additionally needs to be multiplied. The creep rate of the specimen decreases with time in the decay creep stage. When the shear stress level is low, the shear creep rate decreases to a constant value and remains in the steady-state creep stage. With the increase of shear stress, the creep rate of the sample after steady creep increases rapidly, and the creep deformation also increases sharply, finally leading to the failure of the sample. The proposed model can describe the time-dependent characteristics of structural plane and the shear creep characteristics of rock masses with weak structural planes comprehensively. © 2021, Central South University Press. All right reserved.