不同瓦斯压力对构造煤煤体渗流性能的影响

Impact of Different Gas Pressures on Seepage Performance of Tectonic Coal Bodies

文章利用三轴渗流实验装置,对屯兰矿区构造煤进行了不同瓦斯压力对渗流特性的试验研究。结果表明,在弹性阶段,煤体逐渐压缩,渗透率逐渐降低;在接近屈服阶段时,渗透率降到最低;进入屈服阶段,径向变形增大,煤体扩容,煤体内部产生大的变形破坏,新的裂隙成为瓦斯渗流的主要通道,煤体渗透率增加,达到峰值后煤体破坏,渗透率增加迅速,但不能完全恢复初始渗透率。煤体渗透率变化呈现负指数函数减小,试验范围内渗透率降低达67.32%,但渗透率变化受瓦斯压力的影响程度逐渐减弱。通过不同轴压下渗透率随瓦斯压力拟合发现,渗透率随着瓦斯压力的增大符合负指数函数关系。

The article conducts an experimental study on the seepage characteristics of tectonic coal in the Tunlan Mining Area under different gas pressures using a triaxial seepage experimental device.The results indicate that the permeability of coal is gradually decreased with the compression of the coal body during the elastic stage.The permeability reaches its lowest point when approaching the yield stage.Upon entering the yield stage,the radial deformation increases,causing the expansion of coal,and large deformation and damage occur inside the coal body.New cracks become the main channel for gas seepage,and the permeability of the coal body increases.After reaching the peak,the coal body is destroyed,and the permeability increases rapidly but cannot fully recover to its initial level.The change in coal permeability presents a negative exponential function,with a decrease of up to 67.32%within the scope of the experiment.However,the impact of gas pressure on the permeability change gradually weakens.According to the fitting of permeability with gas pressure under different axial pressures,it is found that the permeability conforms to the negative exponential function relationship with the increase of gas pressure.