CAJ | 학술논문

开展原煤在热-力作用下煤热膨胀与吸附瓦斯解吸研究对于深入理解深部煤岩失稳破坏机制有重要意义。通过对四川白皎矿和徐州张双楼矿的原煤施加不同温度-应力条件，获取煤的热变形、解吸气体运移以及煤的力学性质的热响应。试验结果表明：白皎煤在低于35℃条件下表现为膨胀变形；在高于35℃恒温环境下，煤体变形表现为先膨胀后收缩趋势。张双楼煤在低于60℃条件下表现为先膨胀后会出现收缩；在高于60℃恒温环境下，煤样趋向整体膨胀。其结果说明，煤岩在热环境中的变形行为取决于煤基质的热膨胀与解吸收缩之间的竞争结果。煤吸热升温后孔隙中解吸气体数量增多，煤样在受载压缩变形过程中显现出复杂解吸气体排放特征，包括煤中原生孔隙裂隙压缩闭合排出气体，煤体内不均匀变形导致气体流动，煤体开裂导致气体回流。力学测试结果表明，煤样的单轴抗压强度以及弹性模量随着环境温度上升均表现出下降趋势。其结果为深入理解深部煤层在热-力耦合下渗透率与强度变化机制提供试验依据。
개전원매재열-력작용하매열팽창여흡부와사해흡연구대우심입리해심부매암실은파배궤제유중요의의。통과대사천백교광화서주장쌍루광적원매시가불동온도-응력조건，획취매적열변형、해흡기체운이이급매적역학성질적열향응。시험결과표명：백교매재저우35℃조건하표현위팽창변형；재고우35℃항온배경하，매체변형표현위선팽창후수축추세。장쌍루매재저우60℃조건하표현위선팽창후회출현수축；재고우60℃항온배경하，매양추향정체팽창。기결과설명，매암재열배경중적변형행위취결우매기질적열팽창여해흡수축지간적경쟁결과。매흡열승온후공극중해흡기체수량증다，매양재수재압축변형과정중현현출복잡해흡기체배방특정，포괄매중원생공극렬극압축폐합배출기체，매체내불균균변형도치기체류동，매체개렬도치기체회류。역학측시결과표명，매양적단축항압강도이급탄성모량수착배경온도상승균표현출하강추세。기결과위심입리해심부매층재열-력우합하삼투솔여강도변화궤제제공시험의거。
When coal is recovered by mining, or fluid recovered or injected, complex interactions of stress, gas sorption and thermal expansion have a strong influence on the mechanical and transport properties of coal. In this study, intact coal with endogenetic gas, collected from Baijiao mine and Zhangshuanglou mines in China, were treated by thermal-mechanical loading under different isothermal conditions. A special apparatus is used to measure mechanical parameters of solid and gaseous products released from specimen. It is observed from thermal deformation-time curves of the coals that both the deformation of coals and associated gas desorption are significantly controlled by applied thermal conditions as expected. The results show that Baijiao coals with highly in-situ gas content tend to swell below 35 ℃. And above 35 ℃, the coals first swell and then shrink. For Zhangshuanglou coals with lowly in-situ gas content, the coals exhibit swell, followed by shrinkage of coal matrix under isothermal conditions below 60 ℃. However, the coals tend to expand on the whole when the isothermal conditions are set above 60 ℃. The results indicate that the coal deformation is dominated by competition between thermal expansion and shrinkage of coal solid by the applied temperature. Meanwhile, more thermal-induced desorbing gas flow into pores and cleats of the coal. In this case, the stressed coal is characterized by complex coal-gas interaction under different isothermal conditions. Existing pore gas may be squeezed out during initial compaction of pore and cleat of coal. Ebb and flow of desorbing gas is observed from elastic deformation to failure. In comparison with the data of the two coal samples, both uniaxial compressive strengths and Young’s modulus of the coal samples are found to deteriorate with increasingly temperature conditions. It may help us to gain an insight into temperature dependency of mechanical property of gas-bearing coal.