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利用人工模拟降雨试验研究降雨强度和坡度两因子对海涂围垦区排灌工程边坡侵蚀产沙过程及其对径流水动力学参数的响应关系。结果表明,边坡输沙率随降雨历时增加呈S形曲线增长。随雨强和坡度增大,坡面细沟发育迅速,侵蚀量急剧增加,但在坡度25°附近存在一个侵蚀的临界坡度。高雨强和陡坡下,坡面平均流速显著增大,侵蚀输沙率与平均流速之间呈显著线性正相关关系。试验坡面径流雷诺数较小,变化于8.5~42.6之间,水流剪切力为分散边坡土颗粒的主要作用力;坡面输沙率和平均雷诺数之间呈抛物线正相关关系,且在雷诺数较小时坡面输沙率随雷诺数的增长较缓慢,随水流雷诺数的增大,水流紊乱程度越强,坡面产沙能力越强。坡面径流所受阻力系数均随雨强和坡度增大线性降低,输沙率与Manning糙率系数和Darcy-Weisbach阻力系数均呈线性负相关关系。
Using artificial rainfall experiment to study the relationship between rainfall intensity and slope two factors on the process of slope erosion and sediment yield and hydrodynamic parameters of runoff irrigation in reclamation area. The results show that the slope sediment transport rate increases with the rainfall lasted for a S-shaped curve. With the increase of rainfall intensity and slope, the rill of the slope develops rapidly and the erosion amount increases sharply. However, there exists an erosional critical slope near the slope of 25 °. Under high rainfall intensity and steep slope, the average velocity of the slope increased significantly, and there was a significant linear positive correlation between the rate of sediment transport and the average velocity. The Reynolds number of runoff on the slope is small, varying from 8.5 to 42.6. The shear force of water flow is the main force of the soil particles dispersed on the slope. There is a parabolic positive correlation between the sand transport rate and the average Reynolds number When the Reynolds number is small, the slope sediment transport rate increases slowly with the Reynolds number. With the increase of the Reynolds number, the turbulence of the water flow is stronger and the sediment yield of the slope is stronger. The drag coefficient of slope runoff decreased linearly with the increase of rainfall intensity and gradient. The sediment transport rate showed a linear negative correlation with Manning roughness coefficient and Darcy-Weisbach drag coefficient.