三维土工网防护坡面流水动力学特性试验研究

发布时间：2018-02-24 15:06

本文关键词： 三维土工网垫坡面薄层水流水动力学特性防护机理　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文首先对三维土工网垫主要设计指标进行系统介绍,分析其坡面防护机理。并且为消除下垫面的动态变化对研究结论造成的不确定性,本文对下垫面进行简化,将坡面由动床护坡变为定床护坡,对三维土工网垫防护边坡坡面径流规律进行研究。基于上述研究,本文设计了定床下垫面状态下三维土工网防护坡面流水动力学特性研究的室内模型试验,研究了不同流量(0.6、0.9、1.2、1.5m3/h)、不同坡度(8°、14°、20°、26°、32°)、不同植被覆盖率(25株/m2、50株/m2)状态下坡面流水动力学特性,包括坡面流流速、水深、弗劳德数、雷诺数、阻力系数以及水流功率等参数,得到结论如下:1.坡面流速随流量和坡度的增大而增大,当流量较小时流速增幅较大,而流量较大时增幅逐渐减小;水深随流量的增大而增大,随坡度的增大而减小。流速与流量、坡度的关系以及水深与流量、坡度的关系均可用幂函数的形式表示;2.随着坡度增大而弗劳德数持续增大,受单宽流量的影响较小;雷诺数与单宽流量存在线性关系,且相关度极高,但与坡度的关联性不大;阻力系数随放水流量的增大而减小,并且相对于坡度而言,流量对阻力系数的作用更加明显;3.不同流量不同坡度下,水流功率与坡度、流量都呈现正相关关系,流量对坡面流功率的影响略大于坡度对坡面流功率的影响;4.植被覆盖可以有效降低坡面流的流速,与无植被覆盖裸坡相比,25株/m2、50株/m2覆盖率下水流的平均流速降低14.3%和26.3%。此外,植被覆盖对于绕流雷诺数、弗劳德数有一定的降低作用,对阻力系数有一定的增加作用,且覆盖率越高作用越突出,但随流量增大作用趋于不明显。
[Abstract]:In this paper, the main design indexes of 3D geotextile cushion are introduced systematically, and the mechanism of slope protection is analyzed. In order to eliminate the uncertainty caused by the dynamic change of the underlying surface, this paper simplifies the underlying surface. The slope surface is changed from moving bed slope protection to fixed bed slope protection. In this paper, an indoor model test was designed to study the dynamic characteristics of income on the slope of 3D geotechnical network protection under the condition of fixed bed underlying surface. The dynamic characteristics of income were studied under the condition of different flow rate of 0.66 ~ 0.9 ~ 1.2 脳 1.5 m ~ (3 / h), different gradient of 8 掳~ 14 掳~ 20 掳~ 20 掳~ 20 掳~ 26 掳~ (32 掳), different vegetation coverage of 25 plants / / m ~ (2) / m ~ (2), different flow rate of 0. 6% / m ~ (2) / L ~ (-1) / m ~ (2) / m ~ (2). Including flow velocity, water depth, Froude number, Reynolds number, drag coefficient and flow power. The conclusions are as follows: 1. The flow velocity on the slope increases with the increase of flow rate and gradient, and increases greatly when the flow rate is small. When the flow rate is larger, the increase of water depth increases with the increase of flow rate, and decreases with the increase of gradient, and the relationship between flow velocity and flow rate, the relationship between water depth and flow rate, and the relationship between water depth and flow rate, The relationship of slope can be expressed by power function. 2. With the increase of slope, Froude number increases continuously and is less affected by single wide flow, Reynolds number has a linear relationship with single wide flow, and the correlation is very high, but it has little correlation with slope. The resistance coefficient decreases with the increase of discharge flow, and the effect of flow on drag coefficient is more obvious than that of slope. 3. Under different flow and different slope, there is a positive correlation between flow power and gradient and flow rate. The effect of flow rate on slope flow power is slightly greater than that of slope gradient on slope flow power. Vegetation cover can effectively reduce the flow velocity of slope flow. Compared with bare slope without vegetation, the average flow velocity of 25 plants / m ~ 2 / m ~ 2 / m ~ 2 decreased by 14.3% and 26.3 / m ~ 2, respectively. Vegetation cover has a certain effect on decreasing Reynolds number and increasing drag coefficient, and the higher the coverage is, the more prominent the effect is, but the effect tends to be less obvious with the increase of flow rate.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV131.6

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