Study On Chaotic Dynamical System Evolution Of Coal And Gas Outburst

Coal and gas outburst is a very complicated phenomenon of dynamics in coal mines. It is not only one of the most serious calamities that threaten the safe yield, but also a difficult problem in science that needs thrashed out urgently. This dissertation has done a systematic study on the prediction of coal and gas outburst from the chaotic dynamics.This dissertation advances the dynamical retrieval comprehensive supposition based on the comprehensive supposition. Because the complexity of the system , the outburst mechanism and the physical process have still rested on the phase of supposition. The comprehensive supposition which considers coal and gas outburst is caused by earth stress, gas and physical mechanics character of coal, is certificate universally, but quantitative analysis is not done in the weight of the factors. Dynamical retrieval comprehensive supposition thinks the process of outburst is a process of dynamical evolution. According to the principle of system reciprocity, the factor index in original system contains all the information in evolution of the dynamical system. So the time series show the system's evolution. In the meaning of differential coefficient homeomorphism time series is isomorphic to a phase space. Analysis the evolution track of phase space will predict the weight of index in the same time and the same place, as well as retrieval to the original coal and gas system. It is possible that the dominant factor will be got through analyzing the result of retrieval.The warp between mathematical model and practical problem must be exist, because the deformation and destruction of coal and rock will affect the mechanics parameter, as well as the study on fluid and solid coupling constitutive relation is deduced from experiment. This dissertation suggests a new method to analyze outburst. According to Takens theorem in dynamics, if an appropriate embedding dimension is given, the time series which reflect the original system will be embedded in a reconstructed phase space, the attractor in the system will be retrieved. From the type of the attractor, the situation of outburst will be attained. In this way, a mapped isomorphic system which represents the fluid and solid coupling of coal and gas is gained, and that equivalent dynamic behavior is got.Based on the chaotic dynamic theory, the theory and method of time series in discrete dynamic system is analyzed, new thought ways in chaotic time series prediction is brought forward creatively. The new predict method based on reconstructed phase space including piecewise linear approximations, cubic spline function approximations, Fourier function approximations wavelet approximations and gauss function approximations.The multi-fractal dimension in gas distribution and the corresponding mathematic model are given after analyzing the fractal feature in hole and cracks of coal, gas distribution as well as fault evolution process. The comparatively invariant fractal dimension is measured coal and gas outburst. There are many ways to calculate fractal dimension, it is a new criterion to predict outburst.The Lyapunov exponent is used to distinguish the chaotic feature in system, if the system is chaotic, it can be analyzed in chaotic dynamic method, including coal and gas outburst system if the time series of system is chaotic, and many new way of prediction can be used in the field. The C-C method ,G-P arithmetic are used in phase space...