突出煤层表面裂隙特征与瓦斯吸附/放散特性关系实验研究

Experimental study on relationship between surface fracture distribution and gas adsorption as well as emission characteristics of outburst coal seam

瓦斯吸附、放散特性对于煤与瓦斯突出灾害预测、检验与防治十分重要,且与煤体裂隙结构特征密切相关。选取东曲煤矿2#、4#、8#和9#煤层的煤体试样,利用分形维数表征煤体表面裂隙特征,研究了煤体裂隙分布与瓦斯吸附、放散特性参数之间的关系。结果表明:基于分形理论求解了煤体表面裂隙分布的分形维数,取值范围为1.4~1.5,原生裂隙发育程度为9#煤层>4#煤层>8#煤层>2#煤层;通过瓦斯吸附、放散实验测试分析了煤体等温吸附常数及瓦斯放散初速度,吸附常数a取值范围为34.180~36.920 m3/t,瓦斯放散初速度取值范围为12~18 mmHg,上述参数的大小顺序与分形维数值一致。统计分析了东曲煤矿煤体分形维数与瓦斯吸附、放散特性参数的相关性,结果表明二者呈显著正相关性,分形维数能够表征该煤矿煤体瓦斯吸附与放散的特性与能力。

Gas absorption and emission characteristics are very important for the prediction,inspection and prevention of coal and gas outburst disasters,which are related to the structural distribution characteristics of coal fractures closely.In this paper,the coal samples of No.2,No.4,No.8 and No.9 coal seams in Dongqu Coal Mine are selected,and the fractal dimension is used to quantitatively characterize the distribution of coal surface fractures.The relationship is studied between the characteristic parameters of fracture distribution and gas absorption and emission.The results show that the fractal dimension parameters of the fracture distribution on the coal surface are solved by fitting based on the fractal theory.The value range of the fractal dimension parameters is 1.4-1.5,and the development degree of primary fractures is No.9 coal seam>No.4 coal seam>No.8 coal seam>No.2 coal seam.The isothermal adsorption constants of coal and the initial velocity of gas emission are analyzed through the gas adsorption and emission experiment.The value range of adsorption constants a is 34.180-36.920 m3/t,while the value range of initial velocity of gas emission is 12-18 mL/s,which is consistent with the fractal dimension value.The correlation between fractal dimension parameters and gas adsorption and emission parameters of coal in Dongqu Coal Mine are statistically analyzed.It shows that there is a significant positive correlation between them.The fractal dimension value can characterize the values and capabilities of gas adsorption and emission of coal in this coal mine.