黄土坡面细沟侵蚀能力的水动力学试验研究

A STUDY ON HYDRAULIC CHARACTERISTICS OF FLOW FOR PREDICTION OF RILL DETACHMENT CAPACITY ON LOESS SLOPE

建立以水动力学为基础的侵蚀预报模型，必须解决影响土壤侵蚀发生过程及其强度的各水力要素的合理计算问题。本文通过室内径流冲刷试验，研究了黄土坡面细沟侵蚀发生的水动力学机理及其输沙特征，探讨了细沟侵蚀预报模型中，细沟侵蚀能力计算时所涉及的土壤及有关径流的水力参数：土壤侵蚀性系数，细沟侵蚀发生的临界切应力，细沟径流的平均流速，Ｍａｎｎｉｎｇ糙率系数，以及反映细沟断面形态特征的系数的估算问题。

Summary In recent years, some Process-based soil erosion Predictihon models are Proposed in order to promote soil loss Prediction on slope. In such Prediction models, estimation of hydrodynamic Parameters in soil erosion processes is the key to predict soil loss on slope exactly. Based on the runoff experiments in laboratory, the mechanism of rill erosion and sediment transport in rill are studied and the method to estimate the hydraulics of flow in rill, such as critical shear stress for rill initiation, mean velocity of flow in the rill, Manning roughness coefficient soil erodibility for rill erosion, as well as rill section characteterishc are discussed in thes paper.