三轴应力下软煤和硬煤对不同气体的吸附变形特性
Adsorption deformation characteristics of soft coal and hard coal to different gases under triaxial stress condition
-
摘要: 为了深入研究煤体与瓦斯相互作用的变形特性,利用自主研发的三轴应力下煤样吸附变形动态测试系统,开展三轴应力状态下CO2和CH4气体在软煤和硬煤中吸附量以及吸附变形的动态测试试验,建立了三轴应力下煤样吸附气体变形模型。试验结果表明:①软煤和硬煤在三轴应力条件下对CO2和CH4气体的吸附曲线符合Langmuir方程。三轴应力状态下软煤的吸附能力远大于硬煤的吸附能力,且两种煤样对CH4的吸附量都小于CO2。②在应力恒定状态下,软煤吸附气体后的变形大于硬煤吸附气体后的变形。③软煤与硬煤在三轴应力下的吸附变形动态演化过程可以划分为初始快速变形阶段、缓慢变形发展阶段和变形稳定阶段3个阶段。④三轴应力下煤样的变形量随着吸附量的增加而增大。Abstract: In order to further study the deformation characteristics of interaction between coal and gas, a dynamic test system of adsorption deformation for coal sample under triaxial stress was developed to measure the adsorption capacity and adsorption deformation of carbon dioxide and methane in soft coal and hard coal of the dynamic test under triaxial stress, and established the deformation model of gas adsorbed by coal under triaxial stress. The results show that: ① The adsorption curves of soft coal and hard coal to carbon dioxide and methane gas under triaxial stress condition meet with the Langmuir equation.The adsorption capacity of soft coal is larger than hard coal under triaxial stress condition, and the amount of methane adsorbed by both coal samples is less than that of carbon dioxide. ② Under the condition of constant stress, the deformation of soft coal adsorbed gas is greater than that of hard coal adsorbed gas. ③ The dynamic evolution process of adsorption deformation for soft coal and hard coal under triaxial stress can be divided into three stages: initial rapid deformation stage, slow deformation development stage and deformation stability stage. ④ The deformation of coal samples increases with the increase of adsorption capacity under triaxial stress.