坡面土壤分散—径流挟沙动力学模型及应用

Dynamic Model of Soil Dispersion and Sediment Delivery by Runoff on Slope and Its Application

将坡面土壤侵蚀过程中的受力状态变化分为粘聚态、分散态、挟沙扩散态三种动力结构状态,揭示出土壤分散与径流挟沙的动力学机理;建立降雨、径流、土壤水、入渗、土壤阻力等动力—能量转化方程,进而建立以土壤分散、径流挟沙物理模型为核心的坡面土壤侵蚀动力学模型及参数体系,研发出土壤侵蚀动力学模型基本参数的有效辨识途径与方法.利用陕西子洲团山沟径流小区7次径流泥沙观测资料进行模拟,断面单宽输沙率模拟平均误差率为11.71%,复相关系数达到0.9512.WEPP模型模拟平均误差率在40%以上,USLE模型模拟平均误差率在18%以上;本文模型模拟优度、精度良好,实用性、有效性明显提高,可为加快土壤侵蚀机理和物理模型的深化研发提供新的思路和途径.

Change of the force states in soil erosion processes on slope is classified as three dynamic states of cohesion, dispersion and sediment delivery. The dynamic mechanisms of soil dispersion and sediment delivery by runoff were revealed on the basis of the classification. A power-energy conversion equation incorporating rainfall, runoff, soil water, infiltration, and soil resistance was found. Accordingly, a dynamic model of soil erosion and its parameter system were then constructed, with the core component of the physically-based model of soil dispersion and sediment delivery by runoff. The effective ways and techniques for the parameter identification were provided. A simulation work was made using 7 groups of data observed from the runoff plots in Tuanshangou, Zizhou County, Shaanxi Province. The averaged error from the simulation of sediment transport rate per unit width was found to be I I. 71% and the multiple correlation coefficient 0. 9512. The averaged error for the simulation by WEPP model was above 40% and for the simulation by USLE model, above 15%. The constructed model has high simulation goodness and precision and is evidently improved in practicality and effectiveness. Results from the study can provide some new ideas and ways for the systematical and deep research on the mechanisms and physically-based modeling of soil erosion.