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煤层气开采过程中,伴随着煤层气不断地吸附、解吸和渗流,煤体产生变形,极易导致煤和瓦斯突出事故。以晋城天地王坡煤矿为例,通过实验室内试验,模拟煤层气在复杂地层漫长的形成和逐渐开采过程,得到了孔隙压力与解吸量、应变的变化关系,并拟合得出其相应关系表达式,揭示了一些新的规律:(1)初期解吸速度较快,解吸量随时间的增长而不断增加,后期解吸速度减缓,解吸量逐渐趋于稳定;(2)孔隙压力与解吸量、应变呈现抛物线曲线关系,随孔隙压力的升高,吸附和膨胀变形占主导,其值均在增大;(3)存在最小孔隙压力值,随孔隙压力的增大,解吸时间增长,孔隙压力越小,吸附解吸规律越不明显,对于晋城天地王坡煤矿3#煤样,该值在1.0MPa左右;(4)不同加载方式对解吸量和变形量影响较大,先部分加载吸附后全部载荷解吸结果同比加全部载荷吸附解吸结果高13%～77%。试验结果可为煤层气(CBM)抽放安全和煤与瓦斯突出防治提供理论依据。
During the process of coalbed methane exploitation, with the continuous adsorption, desorption and seepage of coalbed methane, the deformation of the coal body can easily lead to coal and gas outburst accidents. Taking Wangpo Coal Mine in Jincheng Tiandi as an example, the relationship between pore pressure and desorption capacity and strain was obtained through laboratory experiments to simulate the long formation and gradual mining process of coalbed methane in complex strata, and the corresponding relationship was obtained (1) the initial desorption rate is faster, the desorption amount increases with time, the desorption rate slows down and the desorption amount tends to be stable gradually; (2) The pore pressure and desorption amount, With the increase of pore pressure, the adsorption and expansion deformation are dominant, and the values are increasing. (3) There is the minimum pore pressure value. With the increase of pore pressure, the desorption time increases and the pore pressure increases The less obvious is the law of adsorption and desorption. For 3 # coal sample of Wangpo coal mine in Jincheng Tiandi, the value is about 1.0MPa. (4) The different loading methods have a great influence on desorption and deformation, The results of desorption plus 13% ~ 77% of the total load adsorption desorption results. The test results can provide theoretical basis for CBM drainage safety and prevention of coal and gas outburst.