【摘要】：河道是一個城市得以生存和成長的重要資源，是一種文化傳續(xù)的物質(zhì)載體。解決河道的現(xiàn)狀問題、徹底改善水質(zhì)，促進(jìn)水系的循環(huán)，增強(qiáng)河道防洪能力，打造一個“水清、岸綠、景美”的河道生態(tài)景觀，營造優(yōu)美的水環(huán)境是一個城市建設(shè)極其重要的部分。本文以李村河為例，在查閱大量文獻(xiàn)基礎(chǔ)上，通過數(shù)值模擬和物理實驗等研究手段，結(jié)合計算機(jī)數(shù)值分析、流體動力學(xué)、泥沙輸運動力學(xué)等多學(xué)科技術(shù)方法，從分析在洪水來襲時不同的景觀方案對應(yīng)的水位和流速等水力要素入手，，得出較為合理的景觀設(shè)計方案，并得出不同的生態(tài)景觀對防洪的影響結(jié)果，由于該方案客觀真實地考慮了多種水力條件和影響因子，結(jié)果證明，數(shù)值模擬和實際模型試驗契合度較高，具有較高的實用價值和指導(dǎo)意義。 本文通過對李村河閘門、植被群以及景觀島高低作為水流的主要影響要素進(jìn)行分析，結(jié)合李村河的地形、地貌，水文氣象資料，給出具體的數(shù)值模擬算法進(jìn)行環(huán)境動力分析。在此基礎(chǔ)上，對不同的分析結(jié)果進(jìn)行了對比研究，得出不同的河道景觀方案對水流的阻水效果不同，進(jìn)而導(dǎo)致在相同的水量條件下水位與流速有很大的差別。 經(jīng)過本文的數(shù)值模擬可以看出洪水行進(jìn)過程中，最高洪水位受糙率的影響很大，除了糙率改變區(qū)域受影響外，其上游也會受到較大的影響，但對于下游其影響較小。糙率變化越大，水位的變化也越大。建議河道中的景觀島盡量做成流線型，且順?biāo)鞣较虿荚O(shè)，盡可能減少其對水流的形態(tài)阻力；同時，景觀島上的水生植被應(yīng)多以柔性植被為主，泄洪時，在洪水較大流速作用下易于彎曲變形，以減少植被形態(tài)高度和附加阻力。岸邊斜坡種植植被時，在洪水泛濫線內(nèi)宜種草本植被，在洪水泛濫線外，可種植高大喬灌木，這樣有助于泄洪。植被群對水流具有很強(qiáng)的阻水作用，糙率越大，景觀對水流的阻力越大，流速越小，水位越高。不同糙率情況下流速的變化幅度趨勢是相同的，只是變化幅度大小不同。糙率越大變化幅值波動越明顯。水流在河道彎曲處比較紊亂，主流靠凹岸底部會不斷對凹岸形成淘刷，加大彎曲處的彎曲程度，不利于泄洪，加大了水流與河床之間的矛盾。所以堤線與河流流向盡量保持一致，兩岸堤線也盡量保持平行，避免出現(xiàn)局部突然變窄或變寬的現(xiàn)象，有利于洪水宣泄。關(guān)于景觀島高度研究發(fā)現(xiàn)景觀島高度的改變對于島上游流速影響較大。 此外，利用小模型進(jìn)行數(shù)值模擬計算可以得到水位與河道左右岸的關(guān)系，同樣也可以模擬出河道中各點的流速，由此分析景觀方案的防洪能力。此方法對景觀防洪分析具有一定的指導(dǎo)作用。
[Abstract]:River is an important resource for the survival and growth of a city, and a material carrier of cultural transmission. To solve the current situation of the river, to improve the water quality thoroughly, to promote the circulation of the river system, to enhance the flood control capacity of the river, and to create an ecological landscape of the river course with "clear water, green shore and beautiful scenery". Creating a beautiful water environment is an extremely important part of urban construction. On the basis of consulting a large number of literatures, this paper takes the Licun River as an example, by means of numerical simulation and physical experiments, combining with computer numerical analysis, fluid dynamics, sediment transport dynamics and other multidisciplinary technical methods. Based on the analysis of hydraulic factors such as water level and velocity of water in different landscape schemes during flood attack, a more reasonable landscape design scheme is obtained, and the effects of different ecological landscape on flood control are obtained. As a result of considering a variety of hydraulic conditions and influencing factors objectively and realistically, the results show that the agreement between the numerical simulation and the actual model test is relatively high, which has higher practical value and guiding significance. Based on the analysis of Lichun River sluice gate, vegetation group and landscape island as the main influencing factors of water flow, combined with the topography, geomorphology and hydrometeorological data of the Licun River, a numerical simulation algorithm for environmental dynamic analysis is given in this paper. On this basis, the different analysis results are compared and studied, and it is concluded that different river landscape schemes have different water blocking effect on water flow, which leads to great difference between water level and velocity under the same water flow condition. Through the numerical simulation in this paper, it can be seen that the maximum flood level is greatly affected by roughness in the course of flood movement. In addition to the affected area of roughness change, the upper reaches will also be greatly affected, but the influence on the downstream is small. The larger the roughness, the greater the change of water level. It is suggested that the landscape islands in the river channel should be streamlined as far as possible and arranged along the direction of water flow to reduce the resistance to the flow as much as possible. At the same time, the aquatic vegetation on the landscape island should be mainly flexible vegetation. When flood is released, it is easy to bend and deform under the action of large flood velocity, in order to reduce the height of vegetation form and the additional resistance. When planting vegetation on the bank slope, the herbaceous vegetation should be planted in flood line, and tall trees and shrubs can be planted outside flood line, which is helpful to flood discharge. Vegetation group has a strong water resistance to the flow. The larger the roughness, the greater the resistance of the landscape to the water flow, the smaller the flow velocity and the higher the water level. The trend of variation amplitude of velocity is the same under different roughness, but the magnitude of variation is different. The larger the roughness is, the more obvious the fluctuation of amplitude is. The flow of water is disordered at the bend of the river channel, and the main stream will form scouring on the concave bank by the bottom of the concave bank, which will increase the bending degree of the bend, which is not conducive to flood discharge and increase the contradiction between the flow and the riverbed. Therefore, the dike line is consistent with the flow direction of the river as far as possible, and the dike line of both banks is also kept parallel as far as possible to avoid the phenomenon of local sudden narrowing or widening, which is conducive to flood discharge. The study of landscape island height shows that the change of landscape island height has a great influence on the upstream velocity of the island. In addition, the relationship between the water level and the left and right bank of the river can be obtained by numerical simulation with a small model, and the velocity of each point in the river can also be simulated, thus the flood control capacity of the landscape scheme can be analyzed. This method has certain guiding function to landscape flood control analysis.
【學(xué)位授予單位】：中國海洋大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TV87;TU984.18

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