侧限压缩条件下砂岩/泥岩颗粒混合物的渗流特性

Seepage characteristics of sandstone/mudstone particle mixture under the condition of confined compression

在地下采矿活动期间很容易形成具有高渗透性的塌陷区,引起地下水的蓄积和渗流,进而导致突水灾害,严重威胁地下开采的安全。为探讨砂岩/泥岩颗粒混合物(GSMM)在塌陷区中的危害机理,本文采用岩石颗粒渗流实验装置,对砂岩/泥岩颗粒混合物的渗流特性(渗透率κ和非达西系数ζ)进行了一系列实验研究。实验结果表明:试样的孔隙率随着侧限压缩位移的增加(试样高度的降低)而逐渐减小。由于加载过程中裂缝和空隙的减少,砂岩/泥岩颗粒混合物的渗透率降低,非达西系数升高。渗流特性的变化趋势会发生局部波折,且泥岩比重更高的试样渗流特性波动更加明显,说明砂岩/泥岩颗粒混合物的渗流特性与侧限压缩位移、颗粒混合物成分、颗粒粒径、孔隙结构等有关。

During the underground mining operation, it was very easy to form the subsidence area with high permeability, causing the accumulation and seepage of groundwater, which leaded to the water inrush disaster and seriously threatened the safety of underground mining. In order to study the harm mechanism of sandstone/mudstone particle mixture （GSMM） in subsidence area, a series of experimental studies on seepage characteristics of sandstone/mudstone particle mixture （permeability κ and non-Darcy coefficient ζ ） were carried out by using the seepage experimental device of rock particle in this paper. The experimental results showed that the porosity of the sample decreased gradually with the increase of confined compression displacement （the decrease of the sample height）. The permeability of the sandstone/mudstone particle mixture decreased and the non-Darcy coefficient increased due to the reduction of cracks and voids during the process of loading. The variation trend of seepage characteristics could occur local fluctuation, and the fluctuation of seepage characteristics of the samples with higher proportion of mudstone was more obvious, which indicated that the seepage characteristics of sandstone/mudstone particle mixture were related to the confined compression displacement, particle mixture composition, particle size and pore structure.