基于荧光示踪法的含裂隙带红黏土边坡渗流特性研究

Study on Seepage Characteristics of Red Clay Slope With Fracture Zone Based on Fluorescence Tracer Method

为准确高效地分析含裂隙带红黏土边坡在降雨条件下渗流特性,基于荧光示踪法和数字图像处理技术,开展降雨条件下不同裂隙带参数红黏土边坡室内模型试验,实时拍摄降雨过程中含裂隙带红黏土边坡模型水分渗流路径荧光图像,通过识别含荧光强度图像,分析边坡模型中坡表湿润锋、暂态饱和区及体积含水率的变化规律。研究结果表明:随着降雨历时增长,对比有无裂隙带边坡,湿润锋深度的变化随裂隙带深度和位置等裂隙带参数的不同呈不同的发展趋势,且裂隙带深度和位置的变化对湿润锋深度影响最大;降雨过程中,湿润锋深度与裂隙带深度呈正相关,而含水率变化幅度与裂隙带深度基本呈现负相关;裂隙带参数对暂态饱和区面积形成的影响程度由大至小依次为深度、位置、角度;暂态饱和区主要出现在裂隙底端及边坡表层,裂隙带深度越小,两处的暂态饱和区越容易连通;裂隙带深度增大时,雨水可沿裂隙直接渗入边坡深处,并在裂隙底端形成大面积暂态饱和区,饱和区内基质吸力减小使土体抗剪强度降低,体积含水率增加使得土体重度增加进而引起下滑力增大,将对红黏土边坡稳定性造成不利影响。

For accurate analysis efficiently with fissure zone of red clay slope under the condition of rainfall seepage features,based on fluorescence tracer method and digital image processing technology,to develop different fissure zone parameters under the condition of rainfall indoor model test of red clay slope containing fissure zone in the process of real-time rainfall shooting red clay slope model water seepage path fluorescence image,by identifying the fluorescence intensity image.The evolution law of surface wetting front and transient saturated zone and the change law of volumetric water content of red clay slope are analyzed.The results show that,with the increase of rainfall duration,compared with the slope without fracture zone,the variation of wet front depth has a different development trend with the difference of other fracture zone parameters,such as the depth and location of the fracture zone,and the change of the depth and location of the fracture zone has the greatest influence on the change of wet front depth of the red clay slope.In the process of rainfall,the depth of wet front of rainwater infiltration is positively correlated with the depth of fracture zone,while the variation range of water content is negatively correlated with the depth of fracture zone.The variation of the distribution position,depth and angle of the fracture zone has a certain influence on the distribution of the area of the transient saturated zone,and the influence degree is depth,position and angle in descending order.The transient saturated zone mainly occurs at the bottom of the fracture and the surface of the slope.The smaller the depth of the fracture zone is,the more easily the two transient saturated zones are connected.Fissure zone depth increasing,the rainwater can be directly penetrate into deep inside the slope along the fissure,and in the formation of crack on the bottom of the large area of the transient saturated zone and saturated zone,the decrease of matric suction to lower shear strength of soil,soil moisture content increases in the volume of severe increased resulting in decline in force,will adversely affect the stability of red clay slope.