砂岩劈裂裂隙多因素影响下可视化渗流规律研究

Visualization study on seepage law considering the effects of multiple factors on sandstone fissures

基于自主研发的可视化试验装置,应用颜色示踪技术,进行空间多角度砂岩裂隙渗流试验;通过采用图像不同灰度面积处理技术、裂隙面积分析方法,进行图像分区并统计其渗流面积,首次从可视化角度得出在不同法向应力、渗透压、倾角等多因素影响下渗流扩散面积比关系式,指出裂隙渗流加速汇集效应和优势扩散面积区域。并基于裂隙面三维形态测试数据,获得裂隙面粗糙度精确JRC值,利用该JRC值得到裂隙面二维粗糙度云图,并与渗流扩散面积图像相结合,从而确定渗流优势路径范围,指出低粗糙区域是渗流的主要过流路径,进而解释了渗流扩散区域会随倾角增大而减小原因,为隧道工程实践中的防渗封堵提供依据。

Based on the self-developed visualization device of experiments, the color tracer technique is used in the test of sandstone fissure seepage spatially and from different viewing angles.By adopting image processing technology of different grayscale area and analysis method of fracture area, the image shall be partitioned and the seepage area shall be statistically calculated.Firstly, the formula of seepage diffusion area ratio under the influences of different normal stress, osmotic pressure, inclination angle and so on is obtained from the visual perspective, and the accelerated gathering effect of fissure seepage flow and the dominant diffusion area are pointed out.Based on the shape features of 3 D fissures and the measured data, the accurate JRC values for the roughness of the fracture surface are obtained, and these JRC values are used for attaining the 2 D roughness contours of fracture surface.Furthermore, the contours are used in combination with the images of seepage diffusion area, and the dominant seepage passage ranges can be determined.It is pointed out that the area of low roughness provides the main seepage passage, and then it is interpreted that the seepage diffusion area may decrease with the increase of the inclination angle of fissure.