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为了探讨受载含瓦斯煤体渗透性的影响因素,利用自主研制的含瓦斯煤热-流-固-力耦合实验装置,研究了不同有效应力、不同孔隙压力和不同温度条件下煤样瓦斯渗透特性,在考虑吸附变形量、孔隙气体压缩量和温度膨胀变化量的基础上,分别建立了受载煤体渗透性与有效应力、孔隙压力和温度之间的定性定量关系。研究结果表明:1)在温度一定情况下,煤样渗透率随有效应力的增大而呈现负指数变化关系;2)将围压轴压固定,在考虑Klinkenberg效应情况下,煤样渗透率与孔隙压力呈现“V”字型变化关系,并根据实验结果,得到了围压为2.0,3.0 MPa条件下Klinkenberg效应发生的孔隙压力临界值;3)不同温度条件下,有效应力与渗透率并非单调函数,而存在一个转折点,在低应力区,渗透率随温度升高而增大,表现为以向外膨胀为主导;在高应力区,透率随温度升高而降低,表现为以内膨胀为主导;根据实验结果,提出了应力与温度共同影响下的渗透率计算式。
In order to investigate the influencing factors of the gas permeability of coal-bearing gas loaded with coal, the self-developed gas-coal-thermal-fluid-solid-mechanical coupling experiment device was used to study the gas permeability of coal samples under different effective stresses, different pore pressures and different temperatures Based on the characteristics of adsorption deformation, the amount of pore gas compression and the change of temperature expansion, the qualitative and quantitative relationships between the permeability of coal and the effective stress, pore pressure and temperature are established respectively. The results show that: 1) Under the certain temperature, the permeability of coal sample shows a negative exponential relationship with the increase of effective stress; 2) When the confining pressure axis is fixed, considering the Klinkenberg effect, The pressure shows a “V” -shaped variation, and according to the experimental results, the critical pore pressure value under the Klinkenberg effect with the confining pressure of 2.0 and 3.0 MPa is obtained. 3) The effective stress and permeability are not different under different temperature conditions Monotonic function, but there is a turning point. In the low-stress region, the permeability increases with temperature, which is dominated by outward expansion. In the high-stress region, the permeability decreases with increasing temperature, As the leading factor. According to the experimental results, the formula of permeability under the common influence of stress and temperature is proposed.