煤与瓦斯突出预测指标多重分形特征分析

Study on Multi-fractal Characteristics of Coal and Gas Outburst Prediction Indicators

为分析工作面前方瓦斯和应力分布及其演化规律,以寺河矿X1301工作面为例,采用多重分形理论,研究工作面煤与瓦斯突出预测指标钻屑量S和钻屑解吸指数K1值的多重分形特征和不同孔深的特征参数Δα和Δf的变化规律。研究结果表明:煤与瓦斯突出预测指标S和K1值在较大尺度内满足标度不变形;S多重分形特征比K1值弱,两者广义分形维数均呈逐渐降低的趋势;S多重分形谱呈现左钩、右钩和钟罩等3种形状,K1值多重分形谱曲线呈现钟罩状;随钻孔深度的增加,参数Δα和Δf变化规律存在差异。

To analyze the distribution of gas and stress in the front of working face,working face X1301 in Sihe coal mine was taken as an example of object of study. Muhi-fractal features of coal and gas burst drilling prediction indexes, the drilling cuttings S and the cuttings desorption index K1 value, were studied by using the muhi-fractal theory. The relationships between the two multi-fractal parameters Aa and Afof S and KI and the depth of drilling were studied by using the theory. Study results show that coal and gas burst prediction indicators, the drilling cuttings S and cuttings desorption index K1 , have multi-fractal fea- ture, and the divisions keep undistorted in a large scale, that the multi-fractal feature of the drilling cuttings S is weaker than that of the desorption index cuttings K value, and generalized fractal dimensions of both S and K have a decreasing tendency, that the multi-fractal spectra in the drilling cuttings S have three kinds of shape （left hooked, right hooked and bell shape）, while the muhi-fractal spectrum of the cuttings desorption index K1 value is bell shape, and that with the increase in the drilling depth, the change laws of two multi-fractal parameters/tc and AfofS and K1 are different.