The coal strength and deformation properties are key factors affecting safe coal mining and high-efficiency coalbed methane (CBM) development. In this paper, reconstituted coal samples are chosen to investigate the weakening behavior of gas on coal strength, meanwhile, its effects on coal deformation are quantitatively evaluated. The results indicate that the weakening degree of gas on coal strength is closely related to the confining stress and gas pressure. Compared with non-gas-saturated coals, the maximum weakening ratios of adsorbed gas to coal strength are 10.58%, 18.12%, 8.55% and 14.65% under the conditions of confining stress CS = 3 MPa and gas pressure GP = 1 MPa, CS = 3 MPa and GP = 2 MPa, CS = 4 MPa and GP = 1 MPa, and CS = 4 MPa and GP = 2 MPa, respectively. Furthermore, the maximum weakening ratios of free gas to coal strength are 18.27%, 36.54%, 14.79% and 29.58%, respectively, under above four conditions. The maximum coal bulk strain decreases as particle sizes of coal powders increase, and it has a maximum value of 0.0227 and a minimum value of 0.0191 in particle size ranges of 0.01–0.041 and 0.5–1 mm. Under the same conditions, the coal bulk strain increases with increasing gas pressure, revealing that coal deformation properties can be enhanced by gas.

煤的强度和变形特性是影响安全采煤和高效煤层气（CBM）开发的关键因素。本文选取再生煤样品研究了气体对煤强度的弱化行为，同时定量评估了其对煤变形的影响。结果表明，气体对煤强度的弱化程度与围压和瓦斯压力密切相关。与非气体饱和煤相比，在围压CS  = 3 MPa，气压GP  = 1 MPa，CS的条件下，吸附气体与煤强度的最大弱化率分别为10.58％，18.12％，8.55％和14.65％。 = 3 MPa，GP  = 2 MPa，CS ＝ 4 MPa和GP  ＝ 1 MPa，CS  ＝ 4 MPa和GP  ＝ 2 MPa。此外，在上述四个条件下，游离气与煤强度的最大削弱率分别为18.27％，36.54％，14.79％和29.58％。煤粉最大粒径随煤粉粒径的增加而减小，在0.01-0.041和0.5-1 mm的粒径范围内，最大值为0.0227，最小值为0.0191。在相同条件下，煤的整体应变随着气压的增加而增加，这表明瓦斯可以提高煤的变形性能。