长江莲石滩航道整治研究

发布时间：2019-06-03 21:26

【摘要】：提高长江上游航道等级是建设长江黄金水道的重要内容,长江上游羊石盘-上白沙水道作为长江干流航道的重要组成部分,起着承上启下的重要作用,将其航道等级从Ⅲ级提高到II级是长江黄金水道建设的重要环节。该河段中钱口石梁为中水险滩,莲石滩鱼鳅石河段为枯水浅滩,关刀碛河段为枯水急流滩,滩险类型多样,滩险成因和边界条件复杂,整治难度较大。因此,开展数学模型研究,以充分发挥其无缩尺效益、方案优化快速、灵敏度检验方便,以寻求有效、合理、经济的航道整治方案,为设计、施工提供科学依据十分必要。本论文采用二维水流数学模型,对钱口石梁和莲石滩滩段的水流特性及其整治措施进行了研究,主要工作内容和研究成果有:(1)基于实测资料探讨工程河段河道历史演变和近期演变规律,总结河床演变规律,分析河道演变趋势。(2)应用钱口石梁和莲石滩滩段实际水文测验资料对二维水流数学模型进行了细致的验证计算,获取了能较好模拟该河段流场的糙率、网格密度等计算参数。(3)运用二维水流数学模型对研究河段进行了多级流量的流场计算,详细分析了滩段的水流条件,莲石滩鱼鳅石河段是枯水急流险滩,枯水期流速较大。该滩上游的钱口石梁、磨盘石对峙江中,束窄航道,导致中枯水流速大、流态坏。(4)根据河床演变分析成果、水流数值模拟结果及实测资料,研究滩险碍航特性,探讨滩险形成原因,钱口石梁是滩段边界极不规则,礁石遍布,石梁挑流束流、深槽吸流及水流扩散等因素综合作用,形成中水险滩。莲石滩鱼鳅石河段主要因河道没有明显的深槽,断面流速沿河宽均匀分布,水流分散,流速较小,输沙能力弱,汛期淤积在航槽内的泥沙枯水期冲刷不够而成滩;关刀碛河段主要成因是枯水河槽浅窄。(5)结合滩险碍航特性成因、航道整治目标和整治原则,开展整治方案的系统研究。针对各滩的碍航问题,进行了单滩整治方案研究,提出了单滩整治方案,然后形成一个整体方案,并对整体方案的整治效果进行了分析研究并优化。结果表明,方案后航道尺度达到设计要求,浅滩枯水流量时的航槽内流速比方案前普遍有所增大,且不会成为急流滩,增加了枯水期航槽泥沙冲刷能力,有利于枯期航槽稳定;急滩段(莲石滩中水及偏小流量)最大消滩判数已降至成滩临界值以下,急滩问题基本解决;同时方案后险滩河段航槽内水流条件也得到了较为明显的改善,水流夹角和横流减小,对船舶通行较为有利。
[Abstract]:Improving the grade of the upper reaches of the Yangtze River is an important part of the construction of the golden waterway of the Yangtze River. As an important part of the channel of the main stream of the Yangtze River, the Yangshipan-Shangbaisha waterway in the upper reaches of the Yangtze River plays an important role in connecting the above and the following. It is an important link in the construction of the golden waterway of the Yangtze River to improve its channel grade from grade III to grade II. In this reach, the Shiliang of Zhongqiankou is a dangerous beach of middle water, the section of fish and Loach of Lianshitan is a dry shoal, and the section of Guandao moraine is a dry beach. The types of beach risk are various, the causes and boundary conditions of beach risk are complex, and it is difficult to regulate. Therefore, it is necessary to carry out the research of mathematical model in order to give full play to its benefit without scale, the optimization of the scheme is fast and the sensitivity test is convenient, in order to find an effective, reasonable and economical waterway regulation scheme, and to provide scientific basis for design and construction. In this paper, the flow characteristics and treatment measures of Qiankou Shiliang and Lianshi beach sections are studied by using two-dimensional flow mathematical model. The main contents and research results are as follows: (1) based on the measured data, the historical evolution and recent evolution of the river course in the engineering reach are discussed, and the evolution law of the river bed is summarized. The evolution trend of river course is analyzed. (2) the mathematical model of two-dimensional flow is verified and calculated by using the actual hydrological test data of Qiankou Shiliang and Lianshitan beach sections, and the roughness which can simulate the flow field in this reach is obtained. Grid density and other calculation parameters. (3) the multi-stage flow field of the studied reach is calculated by using the two-dimensional flow mathematical model, and the flow conditions of the beach section are analyzed in detail. The velocity of flow is higher in dry season. The Qiankou stone beam and grindstone in the upper reaches of the beach confront each other in the middle of the river and narrow the channel, which leads to the high velocity and bad flow pattern of the middle and low water. (4) according to the analysis results of river bed evolution, the numerical simulation results of water flow and the measured data, the dangerous navigation characteristics of the beach are studied. The causes of beach danger are discussed. Qiankou Shiliang is a dangerous beach with irregular boundary, full of reefs, beam, deep trough suction and flow diffusion, and other factors, such as the formation of the beach dangerous beach, the formation of the beach is very irregular, the reef is full of rocks, the deep trough suction and the flow diffusion and so on. The main reason is that there is no obvious deep channel, the cross section velocity is evenly distributed along the river, the flow is scattered, the velocity is small, the sediment transport capacity is weak, and the sediment deposited in the channel in flood season is not washed enough. The main cause of Guan Dao moraine reach is that the dry river channel is shallow and narrow. (5) combined with the causes of beach dangerous navigation characteristics, channel regulation objectives and regulation principles, a systematic study on the regulation scheme is carried out. In view of the navigation hindrance problem of each beach, this paper studies the regulation scheme of the single beach, puts forward the regulation scheme of the single beach, and then forms an overall scheme, and analyzes and optimizes the regulation effect of the whole scheme. The results show that after the scheme, the channel scale meets the design requirements, and the velocity in the channel is generally larger than that before the scheme, and it will not become a rapids beach, which increases the sediment scouring capacity of the channel during the dry season and is beneficial to the stability of the channel in the dry season. The maximum beach elimination judgment of the fast beach section (Lianshi Beach) has been reduced to below the beach critical value, and the problem of the beach has been basically solved. At the same time, the flow conditions in the channel of the dangerous beach reach have also been obviously improved, and the angle and cross flow of the flow have been reduced, which is beneficial to the passage of the ship.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U617

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