黄河包头段弯曲河道水流特性及河道冲淤特性分析

发布时间：2018-04-15 02:15

本文选题：水流特性 + 泥沙沉降、起动　；参考：《内蒙古农业大学》2017年硕士论文

【摘要】：多年来,针对多沙河流面临的问题及目前研究的局限性,结合黄河包头段弯曲河道的实际情况,分析了 2015-2016年黄河包头弯曲河道各断面的水流特性、泥沙输移特性及在二者的共同作用下对河道冲淤造成的影响等。研究的主要内容包括弯道水流特性、泥沙的沉降与起动、含沙量的变化规律及相关影响因素分析等。研究结果表明:(1)弯道水流特性:弯曲河段不同断面凹岸及凸岸流速明显小于中心线流速,弯道的入口及出口断面靠近岸边的流速分布与中心线流速分布相差较大。各个断面在靠近凹岸及凸岸的两条垂线纵向流速分布上下变化程度相同,而在中心线处流速分布较缓,且下部流速变化幅度大于上部流速变化幅度。冰封期流速分布不同于畅流期,在冰盖条件下不同水深处流速满足不同的对数分布状况。(2)河床形态分析:弯道处断面形态总体呈现处凹岸冲刷、凸岸淤积的现象;在冰封期河床形态发生较大变化;冰封期过后,在开河期弯道顶端出现浅滩。(3)泥沙特性分析:经分析不同采样时段泥沙起动流速和河道实测水流流速对比后发现,大部分情况下水流速度起动速度,即大部分情况下悬移质均可移动,反之,水流速度起动流速,即悬移质不易移动,造成河床发生淤积。(4)含沙量变化分析:沿程变化为减小—增大—减小的趋势,即在采样断面中河床呈现淤积—冲刷—淤积的趋势。冰封期含沙量最小,开河后含沙量逐渐增大。该流域的含沙量及挟沙力的变化趋势基本相同,随着季节的变化均呈增大—减小—增大的趋势,且挟沙力的大小与流量变化有较大关系。
[Abstract]:Over the years, the sandy river and the problems facing the limitations of current research, combined with the actual situation of the Yellow River section of Baotou River, analyzes the flow characteristics of 2015-2016 years of the Yellow River Baotou river channel of each section, sediment transport characteristics and under the combined action of the two impact on river silting caused. The main content of the study including the bend flow characteristics, subsidence and sediment incipience, variation of sediment concentration and related factors analysis. The results show that: (1) bend flow characteristics: bending section and concave convex velocity is significantly smaller than the center line velocity, entrance and exit section of the curve of velocity distribution near the shore and the center line velocity distribution the difference is great. Each section near the concave and convex two perpendicular longitudinal velocity distribution change on the same level and at the centerline velocity distribution is relatively slow, and the lower part The velocity range is greater than the upper velocity variation. The velocity distribution in different period of ice flow, in the ice under the condition of different water depths in different velocity satisfies the logarithmic distribution. (2) the riverbed morphology analysis: bend section shows the shape at the convex concave bank, deposition phenomenon; in the period of ice bed configuration change; frozen period, Ford appeared in break-up period curve top. (3) the characteristics of sediment analysis: after the analysis of different sampling periods of incipient velocity and the observed flow velocity comparison found that in most cases the velocity of flow starting speed and that most cases of suspended sediment movement can be, on the other hand, the incipient velocity of flow velocity is suspended shift quality is not easy to move, causing the riverbed sedimentation. (4) analysis of sediment concentration: along the change of paper divies decreases, which is in the river bed sediment sampling section presents Chong Brush - sedimentation trend. Sediment concentration of frozen river after minimum sediment concentration increases. The sediment concentration in the river basin and the trend of sediment carrying capacity is basically the same, with the change of season showed an increasing trend of increase - decrease - and, with size and flow changes capacity has great relationship.

【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV147

【相似文献】