Study on coal seepage evolution mechanism under cyclic loading and unloading of pore pressure

被引：0

作者：

Ye P. ^{[1
]}

Li B. ^{[1
,2
,3
]}

Wu X. ^{[1
]}

Song H. ^{[1
]}

Cheng Q. ^{[1
]}

Xu J. ^{[4
]}

机构：

[1] College of Mining, Guizhou University, Guizhou, Guiyang

[2] Natl. & Loc. Jt. Lab. of Eng. for Effective Utiliz. of Regional Mineral Resources from Karst Areas, Guizhou University, Guizhou, Guiyang

[3] Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources, Guizhou, Guiyang

[4] State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing

来源：

Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | 2023年 / 52卷 / 04期

关键词：

coal; cyclic loading and unloading; gas pressure; permeability; reciprocity theorem;

D O I：

10.13247/j.cnki.jcumt.20220397

中图分类号：

学科分类号：

摘要：

In order to study the influence of the periodic change of pore pressure on the deformation and seepage characteristics of coal, the triaxial servo-controlled seepage equipment for the thermo-fluid-solid coupling of coal containing methane was used to carry out the deformation and seepage test of coal under cyclic loading and unloading of pore pressure. Based on the importance of matrix-fracture interaction, the internal swelling coefficient was introduced to quantify the influence of gas adsorption on fracture bulk modulus, and the Betti-Maxwell reciprocal theorem was further modified to build a coal permeability model controlled by gas adsorption effect. The results show that when the effective stress is constant, the axial strain, radial strain and volumetric strain of coal decrease with the increase of pore pressure; under the same pore pressure, with the increase of cycle times, the volume strain and radial strain of coal decrease, while the axial strain increases. In the process of pore pressure loading, the permeability of coal firstly decreases rapidly and then tends to be flat, while the permeability of coal recovers when unloading, but it is smaller than the loading stage; under the same pore pressure, the permeability of coal decreases with the increase of cycle times. The permeability evolution process presented by the new model is basically consistent with the test results, which indicates that the model can well describe the evolution process of coal permeability under cyclic loading and unloading of pore pressure. The evolution law of internal swelling coefficient under different cycle times is discussed, and it is found that the internal swelling coefficient increases with the increase of cycle times during pore pressure loading. In the process of pore pressure unloading, the internal swelling coefficient decreases with the increase of cycle times. The research results can provide theoretical guidance for rational arrangement of gas drainage boreholes, and have important significance for efficient underground gas drainage and gas disaster prevention. © 2023 China University of Mining and Technology. All rights reserved.

引用

页码：739 / 749

页数：10

共 39 条

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