Abstract
The evolution of coal-rock fracturing system has complex nonlinear and dynamic features. The deformation feature of coal-rock fracturing and evolution rules of coal-rock crack are accurately represented, which have great value on conducting the research of coal-rock permeability feature and solving the problem of coal bed gas production. In this paper, mathematical model of crack evolution was established. Phase space was restructured by C-C method. Micro-crack amount, axial stress and circumferential stress of crack tip were used as study parameters. Correlation dimension, maximum Lyapunov index and Kolmogorov entropy were used as chaos characteristic quantities of crack evolution system. By calculating and analyzing characteristic quantities, results show that crack evolution behaviour has chaos characteristics.