Abstract：The effects of size effect，temperature and stress on the permeability characteristics are analyzed by the experiments. The results show that for homogeneous samples with the same diameter and different lengths，the error of testing value of permeability rate induced by the size effect is less than 10%，while for the heterogeneous coal core，the error is 4% to 40%，or even higher. The development degree of microcrack is the main factor that leads to permeability rate to change greatly. Under loading and unloading of confining pressure，the permeability rate of coal samples with small diameter is more sensitive than that of large-size coal samples；and the permeability rate is more sensitive to the stress than the porosity. When the coal body experiences higher confining pressures，plastic deformation occurs for the pore structure，the coal suffers permanent irreparable damage，and the porosity and permeability rate cannot restore to the initial values. After the coal experiences high temperature，big holes are compressed，but more micropores are developed. Meanwhile，the specific surface area of the coal increases，and the strength decreases. For the confining pressure，there is a critical point. When the confining pressure reaches the critical point，the permeability rate will be greatly reduced. The permeability rate change of raw coal and shaped coal under loading and unloading is consistent，which is an exponential function of the confining pressure.
胡 雄，梁 为，侯厶靖，朱学光，黄伟强. 温度与应力对原煤、型煤渗透特性影响的试验研究[J]. 岩石力学与工程学报, 2012, 31(6): 1222-1229.
HU Xiong，LIANG Wei，HOU Sijing，ZHU Xueguang，HUANG Weiqiang. EXPERIMENTAL STUDY OF EFFECT OF TEMPERATURE AND STRESS ON PERMEABILITY CHARACTERISTICS OF RAW COAL AND SHAPED COAL. , 2012, 31(6): 1222-1229.
SOMERTON W H，SOYLEMEZOGLU I M，DUDLEY R C. Effect of stress on permeability of coal[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1975，12(5/6)：129-145.
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2012, Vol. 31 
