Creep Model and Parameter Identification of Transversely Isotropic Rock Mass

Abstract:

In order to explore the effect of creep deformation characteristics of soft rock on the stress distribution and deformation law of surrounding rock， taking the carbonaceous slate as a research object， based on indoor experiments， theoretical methods and numerical analysis， the Nishihara model is improved to describe the whole creep characteristics of the rock. Then， the improved Nishihara model is expanded to a transversely isotropic creep model， and a three-dimensional equation is derived under the assumption of transverse isotropy. Finally， the creep experimental data are fitted and the creep parameters are inverted according to the three-dimensional equation. The results show that the creep curve of horizontal bedding rock samples changes with the load， and the graded creep deformation of horizontal bedding rock samples and vertical bedding rock samples shows obvious anisotropy. The improved Nishihara model can well adapt to the deformation characteristics of the creep curve of the carbonaceous slate. The parameter value change of the transversely isotropic creep model fully reflects the effect of stress level on the creep of the carbonaceous slate， thus verifying the adaptability and rationality of the improved Nishihara model.