中文摘要：

通过碘-淀粉染色示踪试验,结合数字图像处理技术,分析了裂缝宽度、深度及表面裂缝面积率3个裂缝表征参数对土壤水分入渗的影响。研究结果表明：大裂缝即实际宽度大于1.25 cm的裂缝,其入渗深度超过45 cm,能够促进土壤水分入渗,为水分运移提供明显的优先通道,随着大裂缝宽度的增加,入渗深度在45～65 cm范围内变化,没有明显的规律,小裂缝对入渗的作用不明显。裂缝深度较小时,土壤水分可看作一维半无限均匀运动,而深度较大的裂缝对入渗的影响显著,土壤水分运移表现出明显的优先流特征。表面裂缝面积率与湿润的土体体积具有良好的正相关关系（r=0.95）,建立了一元回归模型,并提出以表面裂缝面积率作为裂缝对入渗影响程度的表征指标,面积率越大,裂缝对入渗的作用越明显。

英文摘要：

To investigate the influence of desiccation cracks on water infiltration patterns,iodine-starch staining experiments were carried out in cracked loamy clay soil. By application of the digital image processing technology and direct measurements,parameters including crack width,depth and area ratio of surface cracks were computed and employed to analyze the infiltration distribution influenced by crack geometric characteristics. The results showed that macro cracks whose width exceeded 1. 25 cm could visibly accelerate water infiltration and provide obvious preferential pathways for water movement.Infiltration depths under macro cracks varied from 45 cm to 65 cm and there was no evident change in infiltration depth when the crack width increased,whereas micro cracks posed little effects on water infiltration. Water infiltration could be regarded as one dimensional semi-infinite homogeneous movement when cracks were narrow and shallow. On the contrary, deep cracks had significant impacts on infiltration,and obvious preferential features were observed around the macro cracks in soil. The results also revealed that area ratio of surface cracks was positively associated with the volume of wet soil（ r =0. 95）,and a quantitative approach was proposed to assess the influence of soil cracks on water infiltration.