煤与瓦斯突出动态前兆的非线性特征研究

基于混沌和分形理论，分析了描述煤与瓦斯突出动态前兆非线性特征的方法和指标．针对重要突出前兆之一——采掘工作面前方煤体瓦斯涌出量动态时间序列（简称Q序列），计算分析了其最大Lyapunov指数，二阶Renyi熵和关联维，证明Q序列具有混沌-分形特征．进一步研究表明，工作面有突出危险状态与无突出危险状态相比，其Q序列的多重分维谱Dq表现出明显的差异，Dq-q曲线由负q区向正q区过渡时在q=0附近区域明显变陡，而无突出危险时段Dq-q曲线过渡较平缓，从而说明有突出危险时煤岩瓦斯动力系统的变化更为复杂．研究结果可望为突出危险性预测提供一种新的思路．

Study on Nonlinear Characteristics of Dynamic Precursor of Coal and Gas Outburst

Based on chaos and fractal theories,the methods and indices for characterizing the nonlinear patterns of dynamic precursors of coal and gas outburst were analyzed.As one of the main outburst precursors,the dynamic time series of gas emission from excavating face,named as Q series in short,was studied in this paper.Through analyzing the largest Lyapunov exponent,the second-order Renyi entropy and the correlation dimension of Q series,it is proved that Q series possesses chaotic and fractal characteristics.Further study of the multifractal characteristics of Q series shows that when there exists outburst danger at the excavating face,the multifractal spectrum Dq of Q series is remarkably different from that while there is no outburst danger.When there is outburst danger,the curve of Dq vs q obviously appears steep near the point that q equals zero.On the contrary,when there is no outburst danger,the curve of Dq vs q varies gently.Consequently it is indicated that while there exists outburst danger,the evolution of the dynamical system of coal/rock containing gas is more complicated,so that it can be expected that the study will provide a new approach to outburst prediction.