贵州黔北地区构造煤与原生结构煤孔隙特征及分形

为了研究煤体在构造作用影响下孔隙结构与分形特征,本文采用低温氮气吸附法、压汞实验等方法,并结合分形理论对三甲煤矿突出孔洞内外煤样孔隙分布进行定量分析。通过MIP与N2GA联合分析,软硬煤临界孔径分别为59nm和86nm。硬煤孔容主要分布在100nm以下的孔隙中,构造煤各孔容分布差异不大,其中中孔和大孔孔容明显高于硬煤,并且构造煤比表面积比硬煤增大4倍多,孔容多出24.5%。根据分形理论分析发现,构造煤渗流孔和吸附孔分形维数分别为3.03和3.77均高于原生煤3.01与3.72；构造煤热力学分形维数高达2.916,构造煤具有更加复杂的孔隙结构和更加粗糙的孔隙表面。

Study on Pore Characteristics and Fractal of Tectonic Coal and Primary Coal in Northern Guizhou

In order to study the pore structure and fractal characteristics of coal under the influence of tectonic action, this paper uses low temperature nitrogen adsorption method, mercury intrusion experiment and other methods, and combines fractal theory to quantitatively analyze the pore distribution of coal samples inside and outside the outburst holes in Sanjia Coal Mine. Through the combined analysis of MIP and N2GA, the critical pore sizes of soft and hard coal are 59 nm and 86 nm, respectively. The pore volume of hard coal is mainly distributed in pores below 100 nm, and there is little difference in pore volume distribution of tectonic coal. The pore volume of medium and large pores is significantly higher than that of hard coal. The specific surface area of tectonic coal is more than 4 times larger than that of hard coal, and the pore volume is 24.5 % more. According to the analysis of fractal theory, the fractal dimensions of seepage holes and adsorption holes of tectonic coal are 3.03 and 3.77 respectively, which are higher than those of primary coal 3.01 and 3.72. The thermodynamic fractal dimension of tectonic coal is as high as 2.916, and tectonic coal has more complex pore structure and rougher pore surface.