黄土陡坡细沟侵蚀动态发育过程及其发生临界动力条件试验研究  

Experimental study of rill dynamic development process and its critical dynamic conditions on loess slope

作　　者：张永东[1] 吴淑芳[2,3] 冯浩[1,2,3] 霍云云 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [3]西北农林科技大学中国旱区节水农业研究院,陕西杨凌712100 [4]武威市水利技术综合服务中心,甘肃武威733000

出　　处：《泥沙研究》2013年第2期25-32,共8页Journal of Sediment Research

基　　金：国家自然科学基金(41101255;40801015);国家863计划(2011AA100503)

摘　　要：研究细沟动态发育过程及其发生的临界动力条件是认识细沟发生和了解土壤侵蚀水动力过程的重要基础。本研究采用室内人工模拟间歇性降雨试验,对20°黄土陡坡细沟侵蚀动态发育、产流产沙过程及侵蚀发生的临界条件进行了研究。结果表明:(1)细沟侵蚀过程为溅蚀-跌坑-侵蚀穴-断续细沟-连续细沟,到第10场降雨结束,细沟侵蚀面积达68.32%,较发育初期增加了6.7倍,最长沟长、沟宽、沟深增加了9.8倍、5倍和3.3倍;(2)随降雨历时增加,各场降雨地表产流量前期迅速增加,随后达到稳定;含沙量变化为前期迅速增加,随后逐渐稳定并略有增加;(3)径流动能、水流功率与输沙率间均呈线性关系,径流动能更能准确揭示坡面土壤分离过程。实验条件下,黄土坡面土壤剥蚀的临界径流动能为0.013J,临界单位水流功率为0.003m/s;细沟侵蚀的临界径流动能为0.045J,临界单位水流功率为0.004m/s。Experimental study of rill dynamic development process and its critical dynamic conditions are the important foundations to understand rill erosion and hydrodynamic process of soil erosion. In this paper, rill dynamic development process, processes of runoff and sediment yield and critical dynamic conditions are stud- ied on loess bare slope of 20 degree through laboratory continuous rainfall simulation. The results show that： （ 1 ） Dynamic development process of rill erosion could be presented as splash erosion-drop pit-erosion points- intermittent rill-continuous rill. To the end of the 10th rainfall, the rill erosion area reached 68.32 percent and increased 6.7 times than initial erosion. The largest rill length, width and depth increased 9.8, 5, 3.3 times, respectively; （2） With the increase of rainfall duration, surface runoff at prophase increased rapidly, then reached stable during every rainfall. Sediment concentration at prophase increased rapidly, then reached sta- ble and increased slightly; （3） There exits a linear relationship between tk, e sediment transport rate and the runoff kinetic energy, or the unit stream power, and the runoff kinetic energy is better related to sediment transport rate. In the experiment, the critical runoff kinetic energy and unit stream power are 0. 013J and 0. 003 m/s for soil detachment on loess bare slope,respectively. And the critical runoff kinetic energy and unit stream power are 0. 045J and 0. 004 m/s,respectively for rill erosion.

关 键 词：黄土陡坡 细沟侵蚀 动态发育 产流产沙 临界能量 

分 类 号：S157[农业科学—土壤学]