台田措施下坡面流土壤侵蚀水动力学特征

Hydrodynamic Characteristics of Soil Erosion in Overland Flow Under Terraced Field Measure

通过野外径流小区放水试验,研究2种台田类型(土坎,石坎)、3种台田级数(1,2,3级)、1种坡度(10°)、3种放水流量(0.5,1,1.5m^3/h)下坡面流土壤侵蚀过程,分析台田措施下坡面流土壤侵蚀水动力学特征。结果表明,台田级数对坡面流流态影响较大,增加台田级数可使坡面流波动性降低,台田类型对雷诺数影响相对较小。土壤分离速率总体随流量增大而增大,相同流量条件下,呈波动性增加后减少且逐渐趋于平稳的特征,两者相关关系用指数函数回归方程拟合(R2>0.840)。同类台田且田面宽度和相同条件下,土壤分离速率与台田级数呈负相关关系,阻力系数与流量呈负相关关系,坡面流土壤分离速率与阻力系数呈负相关关系。研究结果对认识坡面流土壤侵蚀的过程和规律具有重要意义,也为坡面侵蚀物理模型的建立提供参考。

A field erosion simulation experiment was carried out to study overland flow soil erosion process under 2 terrace types(soil,stone),3 terrace ridges(1,2,3 ridge),1 slope gradients(10°),and 3 water flow rates(0.5,1,1.5 m^3/h).The hydrodynamic characteristics of soil erosion in overland flow under terraced field measure were analyzed.The results showed that the terrace ridge had a great influence on the flow state of the overland flow.The Increasing in the number of terraces could reduce the fluctuation of the overland flow.The influence of terrace types on the Reynolds number was relatively small.The overall soil detachment rates increased with the increase of flow rates.Under the same flow conditions,the soil detachment rates increased first and then decreased,and gradually stabilized.The correlation between the two was fitted by exponential function regression equation(R 2>0.840).For the similar terrace type and field width,and under the same conditions,the soil separation rates were negatively correlated with the number of the field,and the drag coefficient was negatively correlated with the flow.The soil separation rates and the drag coefficient were negatively correlated.The research results could be great significance for understanding the process and law of soil erosion on overland flow,and also provide reference for the establishment of physical model of overland erosion.