水库滩库容恢复试验研究

发布时间：2018-04-23 14:03

本文选题：水库淤积 + 滩库容恢复　；参考：《重庆交通大学》2014年硕士论文

【摘要】：现代社会中,水库在防洪、发电、供水、航运等方面为人类社会的发展做出了巨大的贡献。库容是水库发挥各种效益的最直接保障,然而,在河流上修建水库后,由于水位抬高,流速减小,必然造成泥沙在水库中的淤积,直接导致了库容的损失。随着水库有利的优化调度,河槽库容不会有太大变化,但滩地库容损失后极难恢复,出现了“死滩活槽”、“淤积一大片,冲刷一条线”的现象,机械清淤及管道排沙由于费用较高、工程量大、过于消耗人力物力等原因对恢复水库库容的意义不大,因此探寻有效的滩库容恢复途径、针对滩库容的损失进行研究就显得十分必要。本文基于概化水库的滩库容恢复试验,采用冲刷槽清淤、埋管水压渗透清淤以及埋管气压渗透清淤三种不同方法对滩库容的恢复机理进行了初步研究,主要工作内容和研究成果有： (1)利用概化水槽系统进行了淤积体的塑造试验,不仅验证了选定的流量和尾水,还给之后的滩库容恢复试验提供了原始冲刷地形,为研究滩库容的恢复机理奠定了良好的基础。 (2)冲沙槽方案只能依靠水流拖拽力使槽两侧泥沙起动,冲刷过程缓慢。埋管气压渗透方案能使泥沙颗粒起动,但其不能使边滩淤泥向主槽移动且清淤范围较小。这两种方案均不能使滩库容有效的恢复。 (3)提出了一种将槽孔管预埋在水下淤积物底层使泥沙加压液化的输沙方法——埋管水压渗透。压力水流通过渗透孔使泥沙液化并整体向上起动,高滩淤泥向主槽方向移动再加上两侧休止角上方泥沙的崩塌液化作用,最终在管道上方形成顺管道线的三角形输沙横断面,达到阻断河床淤积以及滩库容恢复的目的。 (4)通过试验观测我们发现：压力水流进入上下开孔的槽孔管后,边滩泥沙整体向上起动而后向主槽移动,试验初段清淤极为明显；压力水流进入左右开孔的槽孔管后,靠近主槽的边坡泥沙最先落回主槽,而后边坡逐渐崩塌向高滩蔓延,输沙断面慢慢扩大。 (5)最后对冲刷地形进行测量,发现8mm孔径的槽孔管清淤效果最佳,这说明渗透孔的孔径大小是影响滩库容恢复效果的关键因素,上下开孔的槽孔管其冲刷深度好于左右开孔。
[Abstract]:In modern society, reservoirs have made great contributions to the development of human society in flood control, power generation, water supply and shipping. The reservoir capacity is the most direct guarantee for the reservoir to exert all kinds of benefits. However, after the reservoir is built on the river, because of the elevation of the water level and the decrease of the velocity of velocity, the siltation of the sediment in the reservoir is inevitable, which directly results in the loss of the reservoir capacity. With the favorable optimal operation of the reservoir, the reservoir capacity of the channel will not change much, but it is extremely difficult to recover after the loss of the reservoir capacity in the beach. The phenomenon of "dead beach living trough", "silting up a large area of sediment, scouring a line" appears. Mechanical silt cleaning and pipeline sand removal are of little significance for restoring reservoir capacity due to high cost, large engineering volume and excessive consumption of manpower and material resources. Therefore, an effective way to restore beach and reservoir capacity is explored. It is necessary to study the loss of beach and reservoir capacity. Based on the reservoir capacity restoration test of the generalizable reservoir, the restoration mechanism of beach reservoir capacity is preliminarily studied by three different methods, namely, scour trough, buried pipe hydraulic infiltration and buried pipe pressure. The main work and research findings are as follows: 1) the silt shaping test is carried out by using the generalized flume system, which not only verifies the selected discharge and tail water, but also provides the original scour terrain for the subsequent beach and reservoir recovery test, which lays a good foundation for the study of the restoration mechanism of the beach reservoir capacity. 2) the sand flushing trough can only be started by the drag force of water flow, and the scour process is slow. The barometric permeation scheme of buried pipe can start the sediment particles, but it can not make the silt move to the main channel and the range of desilting is small. Neither of these two schemes can effectively restore the beach and reservoir. In this paper, a method of sand transport, i.e., water pressure permeation, is presented, in which the channel pipe is preburied at the bottom of the silt and the sediment is liquefied under pressure. The pressure flow makes the silt liquefy through the permeation hole and starts up as a whole. The high beach silt moves towards the main channel and the collapse and liquefaction of the sediment above the two sides of the angle of repose, and finally forms a triangular cross section of sediment transport along the pipeline line above the pipeline. To achieve the purpose of blocking the deposition of the river bed and the restoration of the beach and reservoir capacity. Through the experimental observation, we find that after the pressure flow enters the trough pipe with the upper and lower holes, the silt starts upward and moves backward to the main channel, and the silt clearing is very obvious in the early section of the test, and the pressure flow enters the channel pipe with the left and right holes. The sediment of the slope near the main channel first falls back to the main channel, and then the slope collapses and spreads to the high beach, and the sediment transport section expands slowly. Finally, the scour topography is measured and it is found that the channel pipe with 8mm aperture has the best silt cleaning effect, which indicates that the pore size of the permeable hole is the key factor affecting the recovery effect of the beach reservoir capacity, and the scour depth of the trough pipe with the upper and lower holes is better than that of the left and right holes.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV697.31

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