城市河道生态景观对防洪影响的数值研究
发布时间：2018-12-24 21:07
【摘要】：河道是一个城市得以生存和成长的重要资源，是一种文化传续的物质载体。解决河道的现状问题、彻底改善水质，促进水系的循环，增强河道防洪能力，打造一个“水清、岸绿、景美”的河道生态景观，营造优美的水环境是一个城市建设极其重要的部分。本文以李村河为例，在查阅大量文献基础上，通过数值模拟和物理实验等研究手段，结合计算机数值分析、流体动力学、泥沙输运动力学等多学科技术方法，从分析在洪水来袭时不同的景观方案对应的水位和流速等水力要素入手，，得出较为合理的景观设计方案，并得出不同的生态景观对防洪的影响结果，由于该方案客观真实地考虑了多种水力条件和影响因子，结果证明，数值模拟和实际模型试验契合度较高，具有较高的实用价值和指导意义。 本文通过对李村河闸门、植被群以及景观岛高低作为水流的主要影响要素进行分析，结合李村河的地形、地貌，水文气象资料，给出具体的数值模拟算法进行环境动力分析。在此基础上，对不同的分析结果进行了对比研究，得出不同的河道景观方案对水流的阻水效果不同，进而导致在相同的水量条件下水位与流速有很大的差别。 经过本文的数值模拟可以看出洪水行进过程中，最高洪水位受糙率的影响很大，除了糙率改变区域受影响外，其上游也会受到较大的影响，但对于下游其影响较小。糙率变化越大，水位的变化也越大。建议河道中的景观岛尽量做成流线型，且顺水流方向布设，尽可能减少其对水流的形态阻力；同时，景观岛上的水生植被应多以柔性植被为主，泄洪时，在洪水较大流速作用下易于弯曲变形，以减少植被形态高度和附加阻力。岸边斜坡种植植被时，在洪水泛滥线内宜种草本植被，在洪水泛滥线外，可种植高大乔灌木，这样有助于泄洪。植被群对水流具有很强的阻水作用，糙率越大，景观对水流的阻力越大，流速越小，水位越高。不同糙率情况下流速的变化幅度趋势是相同的，只是变化幅度大小不同。糙率越大变化幅值波动越明显。水流在河道弯曲处比较紊乱，主流靠凹岸底部会不断对凹岸形成淘刷，加大弯曲处的弯曲程度，不利于泄洪，加大了水流与河床之间的矛盾。所以堤线与河流流向尽量保持一致，两岸堤线也尽量保持平行，避免出现局部突然变窄或变宽的现象，有利于洪水宣泄。关于景观岛高度研究发现景观岛高度的改变对于岛上游流速影响较大。 此外，利用小模型进行数值模拟计算可以得到水位与河道左右岸的关系，同样也可以模拟出河道中各点的流速，由此分析景观方案的防洪能力。此方法对景观防洪分析具有一定的指导作用。
[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.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV87;TU984.18
本文编号：2390847
[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.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV87;TU984.18
【参考文献】
相关期刊论文 前2条
1 赵瑞娟;刘鸿涛;陈伟;;输水渠道水力糙率计算方法比较[J];东北水利水电;2009年12期
2 周振红,颜国红,吴虹娟;Fortran与VisualC++混合编程研究[J];武汉大学学报(工学版);2001年02期
本文编号：2390847
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