裂隙煤体渗流力学特性试验研究

Experimental study on permeability of fractured coal

煤体裂隙的存在会严重影响其渗流特性.基于裂隙中的水流运动规律,通过施加平行于裂隙面和垂直于裂隙面2种应力不同方向来研究不同荷载方向和大小对含裂隙煤体渗流特性的影响.试验结果表明:(1)当应力方向垂直于裂隙面即时,试样渗透系数会随着应力的增大而减少,且加载初期下降速率较快,之后下降速率逐渐减少,渗透系数与法向有效应力呈负指数关系.(2)当应力方向平行裂隙面时,由于试样的有效水力隙宽增大,阻碍流体流过的能力降低,因此渗透系数会相应的增大,且渗透系数与侧向有效应力呈指数关系.在试验的基础上利用专业绘图软件绘图并对2类数据拟合所建立的负指数和指数关系式能很好的反应渗透系数与有效应力的关系.

The presence of coal fractures will seriously affect its seepage characteristics. This paper,based on flow law of fracture water,studies the influence of loading direction and size on fractured coal seepage law by two kinds of axial and lateral loading. Results show that：（ 1） When applying an axial stress,the specimen permeability coefficient will decrease with the increase of stress,at loading initial the rate of decline is faster,then gradually reduce the rate of decline. The relationship between the permeability coefficient and axial effective stress is negative exponential;（ 2） When the lateral stress is applied,due to the effective hydraulic aperture of the sample increases,the ability to hinder fluid flows is reduced. Therefore,correspondingly increases of the permeability coefficient, the relationship between permeability coefficient and lateral effective stress is exponentially. On the basis of the experiment,negative exponential and exponential relationship can be a good response relationship between permeability coefficient and effective stress which are established by using professional graphics software to fitting two types of data.