模拟植被类型及空间配置对坡面流水动力学特性的影响

发布时间：2018-07-14 19:00

【摘要】：通过室内水槽模拟冲刷试验,研究缓坡坡降1.4%、流量0.6~1.8L/s、非淹没条件下,植被类型(柔性植被、刚性植被)和植被配置格局(棋盘状格局、长条状格局、带状格局)对坡面流水深、流速、流态、达西阻力系数等水动力学特性的影响,探究其规律。结果表明:(1)与裸坡相比,植被具有雍水缓流作用,水深雍高1.4~2.8倍,流速延缓31%~65%,植被格局较植被类型作用更为明显,其中柔性植被、带状格局雍水效果最好。(2)坡面流态指数m显示刚性植被、棋盘状格局条件下水流紊动性最强,而坡面综合指数k显示柔性植被、带状格局对水流作用更强。(3)各试验条件下,水流流型以过渡流为主,主要受单宽流量影响而与植被条件无关;裸坡条件下水流流态为急流,植被覆盖下为缓流,受单宽流量和植被类型影响较小,棋盘状和带状格局影响较大。(4)植被使坡面平均阻力系数较裸坡增加约2.9~20.5倍,缓流条件下阻流效果更好;植被类型较植被格局对阻力系数的影响更大,其中柔性植被和带状、棋盘状格局阻水效果更好,而沿程阻力系数变化显示带状具有明显的波动特性,棋盘状格局较为稳定,即水动力学条件更佳。
[Abstract]:Through the indoor flume simulation scour test, the flow rate was 0.61.8L / s, and the vegetation types (flexible vegetation, rigid vegetation) and vegetation configuration pattern (chessboard pattern, long strip pattern, belt pattern) were studied to the depth of flowing water on the slope. The influence of hydrodynamic characteristics such as velocity, flow state, Darcy resistance coefficient, etc. The results showed that: (1) compared with the bare slope, the vegetation had the function of slow flow of Yong water, the depth of water was 2.8 times higher, the velocity of flow was delayed by 31% and 65%, and the pattern of vegetation was more obvious than the type of vegetation, among which the flexible vegetation. The zonal pattern has the best effect on water flow. (2) the flow index m of slope surface shows rigid vegetation, the turbulence of flow under chessboard pattern is the strongest, but the comprehensive index k of slope surface shows flexible vegetation, and the zonal pattern plays a more important role in water flow. (3) under various experimental conditions, The main flow pattern is transition flow, which is mainly influenced by single width flow and independent of vegetation condition, and the water flow pattern is jet flow in bare slope condition, and the flow pattern is slow flow under vegetation cover, which is less affected by single width flow and vegetation type. (4) compared with bare slope, the average resistance coefficient of slope was increased by 2.9g 20.5 times, and the effect of blocking flow was better under the condition of slow flow, and the effect of vegetation type was greater than that of vegetation pattern, in which flexible vegetation and strip were the most important factors. The chessboard pattern has better water blocking effect, while the variation of drag coefficient along the path shows that the band has obvious fluctuation characteristics, and the chessboard pattern is more stable, that is, the hydrodynamic condition is better.
【作者单位】：北京林业大学水土保持学院;北京市水土保持工程技术研究中心;
【基金】：国家自然科学基金项目(51309006)
【分类号】：S157

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