黄土膨胀性和裂隙对降雨入渗产流影响机理与水文模拟

Abstract: The loess has distensibility (absorbing water and expansion, dehydration and shrinkage). In addition,loess fissure is widely distributed in the Loess Plateau. Loess distensibility and loess fissure greatly influence rainfall-infiltration-runoff in the loess watersheds, but there are few study reports on the influence mechanism and its simulation methodology. Based on rainfall-runoff experiments in laboratory and on-site, the project is to reveal relationships among rainfall, infiltration and runoff influenced by the loess distensibility and fissure. Based on the understanding on the mechanism of rainfall-infiltration-runoff influenced by loess distensibility and loess fissure, the mathematical model of rainfall-infiltration-runoff will be established. Furthermore, the model will be verified with the data of soil moisture and runoff in the different underlying runoff plot. Based on verified model, the distributed watershed hydrological model with the consideration of the influence of the loess distensibility and fissure, will be established and verified in a typical watershed in the Loess Plateau. Finally, the infiltration and runoff influenced by loess distensibility and loess fissure will be analyzed. It is aimed to improve the runoff simulation accuracy in Loess Plateau watersheds through this study.

摘要：黄土具有膨胀性（吸水膨胀，失水收缩），且黄土中分布着大量的裂隙。黄土膨胀性和裂隙对黄土流域降雨入渗产流过程有很大影响，但目前对影响机理与模拟方法研究还很少。本项目拟通过室内外黄土降雨入渗产流观测实验，揭示黄土膨胀性和裂隙对流域降雨入渗产流影响的机理；基于黄土降雨入渗产流机理的认识，构建考虑黄土膨胀性和裂隙影响的降雨入渗产流模型，并通过土壤水分与径流的室内外实验观测数据验证模型。在此基础上，建立考虑黄土膨胀性和裂隙的分布式流域水文模型，通过典型小流域模型应用，对模型进行率定和验证，并就土壤膨胀性和裂隙对流域产汇流影响做出定量分析，以实现提高黄土高原流域径流模拟精度的研究目标。

黄土具有膨胀性（吸水膨胀，失水收缩），且黄土中分布着大量的各种裂隙。黄土膨胀性和裂隙对黄土流域降雨入渗产流过程有很大影响，但目前对影响机理与模拟方法研究还很少。本项目以黄绵土和娄土为典型黄土，通过室内外降雨入渗试验、溴离子示踪剂示踪试验外试验，揭示了黄土膨胀性和裂隙对流域降雨入渗产流影响的机理。基于试验机理认识，以Green-Ampt模型为基础，提出了考虑土壤膨胀性非稳定降雨入渗产流模型（GJGAM）以及模型参数确定方法，并对模型进行了室内试验验证；基于质量守恒定律，提出了膨胀性土壤水分运动模型（GJRID）以及模型参数确定方法，并对模型进行了室内试验验证。进一步地，将GJGAM模型集成到WEP模型，建立考虑黄土膨胀性的分布式流域水文模型，通过典型小流域（南小河沟流域）模型应用，对模型进行了率定和验证，并就土壤膨胀性对流域产汇流影响做出了定量分析，实现了黄土区入渗产流机理分析及提高径流模拟精度的研究目标。