Abstract The pore structure and coal matrix compressibility evolution law and their influencing factors of middle-high rank coals was evaluated based on the combined application of high pressure mercury injection, low-temperature nitrogen gas adsorption and low-temperature carbon dioxide adsorption. The middle-high rank coals are dominated by macropores and micropores, along with lower developed mesopores. The porosity, total pore volume and macropores have an increasing trend with increasing coalification degree. Meanwhile, micropores had gradually become more dominant. Coal matrix compressibility of middle-high rank coals is between 0.55 × 10−10 and 1.42 × 10−10 N/m2, which had significant effects on mesopores, while its influence on macropores rise with the increases of coal rank. There was a negative correlation between coal matrix compressibility and coalification degree, resulting from the increasing peak intensity and elastic modulus during the coalification processes. The polarity of the water molecules tends to reduce the peak strength and elastic modulus of coal. As a result, the deformability becomes more enhanced resulting in increases in coal matrix compressibility. Organic compositions and inorganic minerals have opposite effects on coal matrix compressibility. Inorganic matter can effectively resist coal matrix compressibility, resulting from the higher intensities and elastic features and their roles in supporting cleats and pores while organic matter has the opposite effect. Pore structural features have important influences on coal matrix compressibility. Coal matrix compressibility has a trend of increasing with the increasing in the porosity, total pore volume and macropores or the decreasing in micropores. In the maceral composition, the vitrinite was positively correlated with the peak intensity and elastic modulus of medium rank coal, while inertinite tends to be the opposite. There is a positive correlation between coal matrix compressibility and vitrinite, but the opposite occurs for inertinite, resulting from differences in their mechanical strength and elastic properties.

中文翻译：

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中高阶煤煤基质压缩性影响因素分析

摘要 基于高压压汞、低温氮气吸附和低温二氧化碳吸附的联合应用，评价了中高阶煤的孔隙结构和煤基质压缩性演化规律及其影响因素。中高阶煤以大孔和微孔为主，低阶介孔发育。随着煤化程度的增加，孔隙度、总孔容和大孔隙度有增加的趋势。与此同时，微孔逐渐变得更加占优势。中高阶煤的煤基质压缩率在0.55×10-10～1.42×10-10 N/m2之间，对介孔影响显着，而对大孔的影响随着煤阶的增加而增大。煤基压缩性与煤化程度呈负相关，这是由于煤化过程中峰值强度和弹性模量增加所致。水分子的极性倾向于降低煤的峰值强度和弹性模量。结果，变形能力变得更加增强，导致煤基质压缩性增加。有机成分和无机矿物对煤基质的可压缩性有相反的影响。无机质具有较高的强度和弹性特征，具有支撑割理和孔隙的作用，可以有效抵抗煤基质的可压缩性，而有机质则相反。孔隙结构特征对煤基质的可压缩性有重要影响。煤基质的压缩性随着孔隙率、总孔容和大孔隙的增加或微孔的减少而有增加的趋势。在微晶成分中，镜质体与中阶煤的峰值强度和弹性模量呈正相关，而惰性则相反。煤基质可压缩性与镜质体之间存在正相关关系，而惰性质体则相反，这是由于它们的机械强度和弹性性能不同所致。