黄土陡坡土壤侵蚀临界动力机制试验研究

Experimental study on dynamic mechanism of critical erosion on loess steep slopes

通过室内土槽放水冲刷试验,研究了黄土陡坡径流侵蚀产沙特性。结果表明陡坡径流平均流速随径流量和坡度的增大呈波动趋势增加,而径流雷诺数Re和Darcy-Weisbach阻力系数f随着坡度的增加呈现出先增后减的变化趋势。坡面径流平均含沙率随流量的增加波动增加,随坡度的增加而呈抛物线形式变化,临界坡度值出现在21°和24°之间。进一步的分析结果表明侵蚀量随坡度的变化趋势与Re的变化是一致的,坡面径流侵蚀临界坡度的出现与雷诺数具有密切的相关关系,二者之间的关系式为:W=0.2676Re-55.44。

The flume experiments were conducted to study the soil erosion characteristics on loess slopes. The results show that the average flow velocity increases with the discharge of flow and slope gradient, while Reynolds number （Re） and Darcy-Weisbach friction coefficient （f） of the flow incease first, and decease after the peak. The average sediment content increases fluctuantly with runoff discharge and changes in parabolic form with the increase of slope gradient. The critical gradient is between 21° and 24°. Further analysis indicates that soil erosion and Reynolds number （Re） have a close relation as W = 0. 2676Re- 55.44.