黄土坡面细沟横断面形态及其水流动力学与挟沙特性

Characteristics of Rill Cross Section Morphology,Hydrodynamics and Sediment-carrying Capacity on Loess Slopes

为了探究影响细沟横断面形态特征的因素及细沟水流侵蚀挟沙能力的变化,通过室内水槽试验,研究不同坡度下细沟断面形态发育规律及水流动力学与挟沙特性.结果表明：放水流量为1 000 L/h,坡面细沟水流流速随坡度增大而增大,弗如德数在0.918～2.126之间变化,且绝大多数值＞1.0,雷诺数在1 500～4 900之间变化;随坡度增大,细沟水流侵蚀能力加大,细沟发育速度加快;细沟流量一定条件下,伴随细沟发育,断面形态由宽浅形向窄深式发育,细沟水流流速减小;细沟断面形态系数变化于0.40～0.80之间,主要集中在0.50～0.65的范围内;细沟断面形态指标随细沟潜在挟沙量的增大而降低.

To study the influencing factors of rill cross section morphology and sediment-carrying capacity of rill flow, this research investigated the development regularity of rill cross section morphology characteristics and hydrodynamics and sediment-carrying capacity of rill flow under different slopes in loess area based on flume experiment. The results showed that： Rill flow velocity increased with the increasing slope grade when the experimental flow rate was 1 000 L/h. Froude number varied from 0. 918 to 2. 126, with the majority of the values bigger than 1.0, while Reynolds number varied from 1 500 to 4 900. With the increasing slope grade, the erosion ability of rill flow increased and rill development accelerated. With the rill development under fixed rill flow, rill cross section developed from wide-shallow shape to narrow-deep shape and rill flow velocity decreased. Rill cross-sectional morphology coefficient changed from 0.40 to 0.80, which was mainly in the range of 0. 50 - 0. 65. rill cross-sectional morphology index decreased with the increasing potential sediment-carrying capacity of rill flow.