摘要
土壤侵蚀是中国南方多雨区面临的一个重大环境问题,研究不同降雨条件下红壤坡面的水动力特性,对于认识红壤侵蚀过程具有重要的意义。采用室内人工模拟降雨试验,研究了不同雨强(60、90、120、180、270 mm·h-1)和不同坡度(5°、10°、15°、20°、25°)条件下红壤坡面的侵蚀特征,分析测定了侵蚀过程中的流速、水深及单宽流量,探讨它们随雨强及坡度的变化规律。结果表明,相同雨强下沿程流速随着坡度增大而呈增大的趋势,坡度为20°的流速大于另外3种坡度(10°、15°和25°)的流速;随着雨强的增加,坡面流平均水深不断增大。不同雨强条件下,坡度为10°的坡面径流平均水深相对较大,而在中大雨强下,当坡度为20°和25°时平均水深均处于较低水平;在同一坡度下,坡面单宽流量随着雨强增大而增大,两者呈现较好的线性关系,决定系数均大于0.91;随着坡度的增加,单宽流量在10°和20°附近分别出现先增加后减少的变化趋势,坡度对单宽流量影响存在临界坡度,其变化值在10°附近。试验结果揭示了试验槽内红壤坡面侵蚀过程中雨强、坡度与水动力特性的关系。
Soil erosion is a critical environmental problem in south China. To investigate and understand erosion flow hydraulics could help to understand the erosion processes in this region. An simulated rainfall experiment was conducted to quantify the effects of rainfall intensity （60, 90, 120, 180, and 270 mm·h^-1） and slope gradients （5°, 10°, 15°, 20°, and 25°） on flow velocity, flow depth and unit width discharge on runoff and soil erosion processes on red earth hillslopes. The results showed that in fixed rainfall intensity, the flow velocity increased along the slope length. The flow velocity occurring on the 20° slope was always higher than that on the other slopes （15°, 20°, and 25°）. The average flow depth increased with the increase in rainfall intensity, and higher flow depth occurred on 10°, while lower flow depth occurred on 20° and 25° under the moderate and large rainfall intensity. In the same slope gradient, the unit width discharge significantly and linearly increased with increasing rainfall intensity, withr2〉0.91. In addition, the unit width discharge at first increased and then decreased near 10° and 20°, respectively. The critical slope degree on effects of slope gradient on the unit width discharge and the value was near 10o. Results from this study expanded the understanding of the relationship among slope gradient, rainfall intensity, and erosion processes characteristics.
出处
《生态环境学报》
CSCD
北大核心
2015年第4期638-642,共5页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(41171221)
广东省自然科学基金项目(S2012030006144
S2011020005896)
广东省水利厅委托项目(GPCGD112197FT141F1
GPCGD122197FD096F)
关键词
模拟降雨
红壤
坡面侵蚀
水动力学特性
simulated rainfall
red soil
hillslope erosion
hydrodynamic characteristics
