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- Title
九龙矿构造煤压力作用下孔隙结构及分形变化特征.
- Authors
张贝贝; 沈军平; 金超; 刘剑
- Abstract
In order to explore the impact underground pressure on coal pore structure alteration of tectonic coal in Jiulong Mine, Handan, reptured coal and fragmented coal from the No. 2 outburst coal seam of Shanxi Formation were selected as the research objects. The coal samples were pressurized by the tableting machine. Low-temperature nitrogen adsorption instrument was adopted to perform the adsorption tests on pressurized coal samples and unpressurized coal samples. Pore structural changes of pressurized coal samples and unpressurized coal samples were comparatively discussed and analyzed using the quantitative analysis method of fractal theory and qualitative analysis method of traditional low temperature nitrogen experimental data. The results show that pore structure alterations occurred under the influence of pressure and this impact is more influential for reptured coal samples compared with fragmented coal samples. The contribution of pore volume of fragmented coal didnt change basically. The contribution of pore volume of reptured coal would change, and the volume of micropores contributes more on the whole pore volumes which indicates that the radius of micropores is more likely to be affected than the mesopores and macropores under pressure. The specific surface area contribution of reptured coal and fragmented coal is smaller pores, basically fluctuating around 2 ~ 4 nm, and the contribution range of pore diameter has slightly shifted back, but the amplitude is not large. The fractal dimensions of micropores are the highest with the degree of fit of more than 0. 99, followed by small pores and mesopores with the degree of fit of more than 0. 94 after pressurization of reptured and fragmented coal samples. After pressurization, the complexity of micropores of fragmented coal samples becomes less complex while for small pores and mesopores, the pore structures become relatively more complex but this impact is not obvious. While for reptured coal samples, pore structures of micropores are less complex after pressurization and pore structures of small pores and mesopores become more complex. Hydraulic fracturing of coal seam or roof & floor is suggested to improve methane recovery of No. 2 reptured coal seam of Jiulong coal mine, and for fragmented coal seams, hydraulic flushing the coal seams or hydraulic fracturing of roof and floor are suggested to improve seam permeability.
- Publication
Science Technology & Engineering, 2023, Vol 23, Issue 35, p14955
- ISSN
1671-1815
- Publication type
Article