煤岩超微孔隙结构特征及其分形规律研究

Structural characteristics and fractal laws research in coal and rock ultrafine pore

煤岩超微孔隙结构对煤的吸附和强度性能起到非常重要的决定作用.为了对其进行精确测定,采用了高精度压汞仪对来自8种不同硬度的煤样进行压汞法实验,测定得出超微孔隙结构的所有特征参数.根据压汞法基本原理和分形几何学理论建立了切合实际的煤孔隙分形维数计算模型,利用孔隙特征参数计算出各硬度的孔隙结构分形维数.研究发现:煤孔隙结构具有很好的分形特征,煤体越松软,分形性越好,用分形规律研究煤岩孔隙结构越精确;随着煤体硬度的增加,孔隙分形维数不断降低,煤体抗压强度不断增大;建立硬度与孔隙分形维数之间的定量关系式,可以用硬度定量描述煤的吸附性和抗压强度.研究结论对于煤层瓦斯的运移、瓦斯抽放以及瓦斯突出均有着极为重要的意义.

The ultrafine pore structure of coal and rock plays an important role in coal adsorption and intensity.Some experiments were designed to make the determination precise using a high-precision pressure mercury analyzer with eight kinds of coal samples which were different in hardness to determine all the characteristic parameters of the AMD pore structure.A realistic coal pore fractal dimension calculation model was established on the base of mercury injection method principles and theory of fractal geometry.Calculations were done to learn the pore structure fractal dimension of any hardness using pore characteristic parameters.The results show that the coal pore structure has very good fractal characteristics,and the fractal character become better and better,the fractal laws research of coal and rock pore structure will be more accurate with the coal flaccidness increasing.With the coal hardness increase,the pore structure fractal dimension will decrease and the compression strength of coal will increase.The relation between pore structure fractal dimension and hardness will be founded on that base,and coal adsorption and compression strength will be described by hardness quantitative analysis.These results are extremely significant for coal gas migration,gas drainage and gas outburst.