Permeability characteristics of gas-bearing coal specimens under cyclic loading-unloading of confining pressure

被引：0
|
作者：
Jia H. [1 ]
Wang K. [1 ,2 ]
Wang Y. [1 ]
Sun X. [1 ]
机构：
[1] School of Emergency Management and Safety Engineering, China University of Mining and Technology (Beijing), Beijing
[2] Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing
来源：
Meitan Xuebao/Journal of the China Coal Society | 2020年 / 45卷 / 05期
关键词：
Cyclic loading-unloading; Fracture compressive coefficient; Gas-bearing coal; Permeability; Permeability damage rate;
D O I：
10.13225/j.cnki.jccs.DY20.1112
中图分类号：
学科分类号：
摘要：
The comprehensive supposition of coal and gas outburst confirms the main role of stress, gas and the physical and mechanical properties of coal in the occurrence of coal and gas outburst.The comparative study of permeability response characteristics of reconstituted coal specimens and raw coal specimens under the influence of mining operation is of great significance to reveal the similarities and differences of micro structure damage evolution of the two coal specimens and to clarify whether the reconstituted coal specimens can replace the raw coal specimens for carrying out relevant experimental study.Some seepage experiments were conducted under a cyclic loading of confining pressure on raw coal specimens and reconstituted coal specimens to investigate the response characteristics of permeability to stress.The self-developed triaxial coal and rock permeability experimental system was used to carry out the test.The results show that the response characteristics of permeability to the stress of the two coal samples are similar in general, but there are differences in details.For both types of coal specimens, the permeability decreases with the increase of confining pressure and increases with the decrease of confining pressure.The permeability of any one loading process is greater than the permeability of unloading process.The permeability of the raw coal specimen changes greatly in low confining pressure stage and changes slowly in high confining pressure stage.The permeability of the reconstituted coal specimen changes uniformly throughout loading and unloading processes.The permeability damage rates of the raw coal specimen and the reconstituted coal specimen decrease with the increasing cyclic times of confining pressure and the increasing gas pressure.The fracture compression coefficients of the raw coal specimen and the reconstituted coal specimen decrease with the increase of cyclic times of confining pressure, and increase with the increase of gas pressure.The permeability of raw coal specimen increases with the increase of gas pressure, while that of the reconstituted coal specimen decreases with the increase of gas pressure.It is feasible to use the reconstituted coal specimen instead of raw coal specimen to study the seepage characteristics of gas bearing coal, and it has certain advantages in some specific occasions.However, it is also necessary to pay attention to the detail differences of permeability response characteristics of the two kinds of coal specimens, and the impact of these detailed differences on the reliability of test results. © 2020, Editorial Office of Journal of China Coal Society. All right reserved.
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页码：1710 / 1718
页数：8
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