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为揭示在温度、地应力和瓦斯压力等多场作用下煤与瓦斯(methane)相互作用对煤矿瓦斯抽采、CO2注气强化瓦斯开采及CO2在深部不可采煤层的封存具有的重要意义,更精确地从微观角度观测在多物理场耦合条件下煤瓦斯相互作用的动态过程,研制了一种在多场耦合条件下带显微观测装置的煤瓦斯试验装置。该装置由密封容器与施力夹持机构、气压系统、温度场系统、显微观测系统4部分组成,能够通过显微观测装置结合图像处理技术,直接观测多场条件下煤与不同气体的相互作用所引起的细微变化。利用该装置进行了无应力加载、相同温度、相同气压下的瓦斯、CO2的吸附膨胀试验。研究发现,(1)试件在两种气体的变形大致经历了快速增长、缓慢增长直至平衡3个阶段,类似于吸附等温曲线;(2)试件在CO2气体中达到吸附饱和的时间比试件在瓦斯气体中达到吸附饱和的时间要短;(3)试件在瓦斯气体中的最大线性应变约为0.15%,相同条件下试件在CO2气体中的最大线应变约为0.5%,相同条件下试件在CO2气体中达到吸附饱和时的最大应变比试件在瓦斯气体中达到吸附饱和时的最大应变大3倍左右。研制的装置具有结构简单、直观、精度高的特点。
In order to reveal the importance of the interaction between coal and methane under the action of multiple fields such as temperature, geostress and gas pressure, it is of great significance to gas drainage in coal mine, CO2 gas injection to strengthen gas production and CO2 sequestration in unobtainable coal seams, The dynamic process of coal gas interaction under multi-physics coupling conditions can be observed more accurately from a microscopic point of view, and a coal gas testing device with microscopic observation device under multi-field coupling conditions has been developed. The device is composed of a sealed container, a force clamping mechanism, an atmospheric pressure system, a temperature field system and a microscopic observation system. The microscopic observation device and the image processing technology can directly observe the interaction between coal and different gases under a plurality of conditions Subtle changes caused by the action. The device was used to carry out the stress-free loading, the same temperature, the same gas pressure, CO2 adsorption and expansion test. The results show that: (1) the deformation of the specimens in the two gases generally experienced rapid growth, slow growth until equilibrium three stages, similar to the adsorption isotherm; (2) the sample in the CO2 gas adsorption saturation time than the specimen (3) The maximum linear strain of the specimen in the gas is about 0.15%. Under the same conditions, the maximum strain in the CO2 gas of the specimen is about 0.5%. The same conditions The maximum strain of the specimen in the CO2 gas when it reaches the saturation of adsorption is about three times larger than the maximum strain of the specimen reaching the saturation in the gas gas. Developed device has the characteristics of simple structure, intuitive, high precision.