植被组合方式对坡面流水动力特性的影响  

Effects of Vegetation Combinations on Hydrodynamic Characteristics of Overland Flow

作　　者：朱艳 王平[1] 马岚 胡杰 Zhu Yan;Wang Ping;Ma Lan;Hu Jie(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学水土保持学院,北京100083

出　　处：《水土保持研究》2024年第6期74-85,共12页Research of Soil and Water Conservation

基　　金：国家自然科学基金“湿地表面流中物质弥散过渡过程机理研究”(52179056)。

摘　　要：[目的]明晰坡面流水动力特性响应不同植被组合方式的趋势特征以及不同植被组合覆盖坡面的阻力构成,以期探究植被组合对坡面流的调控机制,为合理布设坡面蓄水保土工程提供参考依据。[方法]通过室内水槽试验,在不同植被组合方式(单一灌木、单一草被、灌草单行交替、灌草块状交替),3个坡度(1°,5°,9°),5种流量(20,30,40,60,80 L/min)条件下分析坡面流水动力参数对植被组合的响应规律、水流阻力变化规律和阻力构成。[结果]不同植被组合对坡面水深、平均流速、流型和阻力系数均有显著影响(p<0.05)。植被存在时水深壅高了1.07~4.17倍,缓流效率为2.35%~64.7%。各试验条件下水流集中分布在过渡流区,不同植被组合覆盖坡面紊动强度表现为灌草组合>单一植被>裸坡。植被覆盖下的坡面阻力系数明显增加,约为裸坡的1.25~25.45倍,阻水缓流能力表现为单一灌木组>灌草交错组>单一草被组>裸坡。坡面阻力受植被组合方式和茎秆影响(p<0.05),单一植被覆盖坡面阻力主要由颗粒阻力和植被阻力构成;灌草交错覆盖坡面阻力不是各阻力简单线性叠加的结果,坡面上各粗糙元间互相干扰会产生附加阻力,且附加阻力随坡度增加出现削弱水流阻力现象,但相同坡度条件下随流量增大呈增强水流阻力趋势。[结论]单一灌木组的阻水缓流效果最好,灌草交错组的效果相似。[Objective]Indoor flume experiments were conducted to clarify the response trend of overland flow dynamics to various vegetation combinations,to explore the composition of resistance covered by different vegetation combinations,and to explore the regulation mechanism of vegetation combination on overland flow,so as to provide reference basis for rational layout of slope water storage and soil conservation projects.[Methods]The research analyzed the response law,flow resistance variation,and resistance composition of overland flow hydrodynamic parameters under the conditions of different vegetation combinations(single shrub,single grass cover,single row alternation of shrub and grass,alternation of shrub and grass,and bare slope),3 different slope gradients(1°,5°,9°)and 5 kinds of discharge(20,30,40,60,80 L/min).[Results]Vegetation had significant effects on water depth,average velocity,flow pattern,and resistance coefficient(p<0.05).Compared to bare slope,water depth was 1.07~4.17 times higher with vegetation,and the velocity decreased 2.35%~64.7%.Besides,most experimental flow fell in the transition states.Turbulence intensity of different vegetation combinations followed the order:shrub-grass combination>single vegetation>bare slope.Furthermore,the resistance coefficient under vegetation cover was 1.25~25.45 times larger than bare slope,and the effect of water blocking and velocity slowing followed the order:single shrub>shrub-grass combination>single grass cover>bare slope.Resistance was affected by vegetation combination and stem characteristics(p<0.05).The flow resistance was mainly composed of particle resistance and vegetation resistance under single vegetation cover.However,the interference of rough elements produced additional resistance under shrub-grass combination cover,which weakened the flow resistance with an increase of slope gradient,but strengthened the flow resistance with an increase in discharge under the same slope condition.[Conclusion]The effect of single shrub group is the best,and the

关 键 词：坡面流 植被组合 阻力系数 阻力构成 

分 类 号：S157.1[农业科学—土壤学]