黄土丘陵区土壤侵蚀链各垂直带能量转化特征研究

Characteristics of Energy Transform in Vertical banding of Soil Erosion Chain in Loess Hilly Region

黄土坡面各种侵蚀方式以水流能量、侵蚀物质及侵蚀微地貌相关联 ,水流能量是制约侵蚀物质和侵蚀微地貌的时空分异的本质原因。研究表明 ,雷诺数 (Re)、费罗德数 (Fr)及过水断面单位能量 (∈ )等复合参数为判别不同侵蚀方式的水动力学指标。根据二维多坡段组合模型实验结果 ,系统分析了土壤侵蚀链内细沟、浅沟及切沟发生的雷诺数、费罗德数及过水断面单位能量指标的变化特征 ,建立起各种侵蚀方式发生变化与侵蚀能量之间的联系。

The various erosion ways of loess slope related to the three actions of running water energy, sediment and microland feature eroded; The running water energy is the essential reason that restrict the time-space difference of sediment and micro-land feature eroded. The results show that Reynolds number and Froud number, unit energy of water-carrying section as major indexes of running water state, can be treated as mechanics indexes. For selecting the proper parameter from the three water mechanics indexes, we found critical kinetic indexes and coefficient of variability as rill occurred through experiment and statistics. According to 2 dimension multi- slope section combination model experiment result, change feature of Reynolds number and Froud members and passing water section unit energy index of rill and shallow ditch and gully in soil erosion chain were analyzed. The coorelations between various erosion patterns and erosion energy were established.