【摘要】 植被发育斜坡土体中普遍存在大孔隙,在强降雨过程中大孔隙产生的优先流加快降雨入渗,影响斜坡稳定。大孔隙结构影响优先流过程和优先流的水动力特性。为探明植被发育斜坡土体大孔隙结构的多尺度特征,本文在分析土体大孔隙研究进展的基础上,提出适用于研究植被发育斜坡土体大孔隙的试验方法。以云南省段家营、头寨、象冲、东月各、白泥山和贵州八渡滑坡的植被发育斜坡土体为研究对象,采用挖掘法、染色示踪法、CT扫描法、SEM法定性和定量分析植被发育斜坡土体大孔隙的多尺度几何形态和分布特征。研究表明:挖掘法、染色示踪法、CT扫描法、内窥镜检查和SEM法适用于分析植被发育斜坡土体的大孔隙结构;植被发育斜坡土体的大孔隙有腐烂根系通道、根-土间隙、动物通道、团聚体间大孔隙、土-石间隙、干缩裂隙和成因不明大孔隙,其中前四种是主要类型;各种大孔隙相互交织组成大孔隙网络系统;受到植物物种、树龄、动物物种、土体生态系统和立地条件的影响,不同类型大孔隙的多尺度几何形态和分布特征不同。将先进技术手段与染色剂溶液降雨模拟示踪试验结合起来,研究大尺度的大孔隙三维几何形态和分布特征是未来的主要工作。更多还原

【Abstract】 Macropores are richly developed in well vegetated slope soils,where the preferential flow could facilitate infiltration under the circumstance of heavy precipitation,thus influencing slope stability.The preferential flow process and hydrological regime are dominated by the structure of macropores.In order to study the multi-scale features of macropore structures in well vegetated slope soils,researches on soil macropores were comprehensively reviewed,and in this study a practical approach to macropore examination in well vegetated slope soil was proposed.Several well vegetated slopes in Duanjiaying,Touzhai,Xiangchong,Dongyuege,Baini Mountain(Yunnan province,China) and Badu landslide(Guizhou province,China) were performed as a case study,and tunneling method,dye tracer method,X-ray computerized tomography scanning and scanning electron microscopy(SEM) were combined to qualitatively and quantitatively analyze the multi-scale geometry morphology and distribution characteristics of macropores.The results showed that tunneling method,dye tracer method,X-ray computerized tomography scanning,SEM and endoscopy were suitable to analyze macropores structures in well vegetated slope soils.Macropores in well vegetated slope soils composed of decayed root channels,root-soil interstice,animal burrows,inter aggregate porosity,soil-stone interstice,desiccation cracks and macropores without knowing origin.Thereinto,decayed root channels,root-soil interstice,animal burrows and inter aggregate porosity were primary macropores.Different types of macropores were interconnected,which constituted an important macropores networks.Influenced by plant species,tree-age,animal species,soil ecosystem and site condition,different types of macropores had distinct geometry morphology and distribution properties.It is necessary to combine tracer solution rainfall simulation infiltration experiment with advanced technologies in assessing large-scale three-dimensional geometry morphology and distribution properties of macropores networks.更多还原