小范围内涝精细化积水分布研究

 2022-04-18 10:04

论文总字数:34675字

摘 要

随着气候变化和城市化的发展,城市积水问题日益严重,小范围内涝积水分布的精细化研究逐渐成为当下研究热点,而如何利用数值模拟等手段精确得出内涝范围内的积水分布具有重要研究意义。

通过采集地形地貌、降雨水文等基础数据,构建了南京市江宁区某路段及周边区域的城市水文雨洪模型,研究城市积水的精细化分布及其影响因素。从径流深度、节点洪流和水量平衡三个角度,采用径流深度计算公式、二维一般分布数据插值、等体积法和地表径流过程线等方法求解积水信息。通过研究区域模拟结果误差表明模型具有良好的准确性。在此基础上设计5a和10a重现期、120min历时和180min历时的四种降雨条件,定性定量分析不同描述方式下小范围积水分布的特点,并对影响研究区域积水分布的因素做出评价。主要结论如下:

(1)不同工况下地表径流严重的区域均有坡度较大、地势较低和存在汇流现象等特征;洪流严重的节点,存在与其相连接的子汇水区地表径流严重或多块子汇水区径流向其汇集的现象。

(2)采用不同描述方式获得的积水淹没水位、最大淹没深度和淹没面积结果相近,且在积水区域分布上呈现出相同的规律:城市降雨积水主要分布在地势较低洼的区域,并且以道路为扩散渠道;随着降雨强度由小到大,积水分布先呈现出沿道路分布的特点,当淹没水位达到一定高程,积水分布呈现出优先淹没道路两侧地势较低的建筑区广场的特点。

(3)调整地形高程能够大幅减少积水最为严重的区域,显著降低区域内最大积水深度,但由于缺少地势低洼区域的蓄水作用,将增大积水面积;改造下垫面能够显著降低地表径流量,降低地表径流深度,一定程度上能缓解城市地表积水问题;增大雨水口的泄水能力能显著减小研究区域内的积水量,整体降低研究区域内的积水深度,使积水较为严重的区域面积较大幅度地缩小。

关键词:城市积水;积水分布;精细化;影响因素

Abstract

With the development of climate change and urbanization, the problem of urban water logging is becoming more and more serious. The fine research on the distribution of small scale waterlogging has gradually become a hot spot of current research, and how to use numerical simulation and other means to accurately obtain the distribution of waterlogging has important research significance.

By collecting basic data such as topography and landform, rainfall and hydrology, the urban hydrological storm flood model of a section of Jiangning district in Nanjing and its surrounding areas was constructed to study the fine distribution of urban water and its influencing factors. From three angles of runoff depth, nodal flood and water balance, runoff depth calculation formula, two-dimensional general distribution data interpolation, equal volume method and surface runoff process line were used to solve water information. The simulation results show that the model has good accuracy. On this basis, four rainfall conditions of 5a and 10a recurrence period, 120min duration and 180min duration were designed to qualitatively and quantitatively analyze the characteristics of small range water distribution under different description methods, and evaluate the factors affecting the water distribution in the study area. The main conclusions are as follows:

(1) The regions with serious surface runoff under different working conditions are characterized by large slope, low topography and confluence. At the nodes with severe flood, there is a phenomenon that the surface runoff in the sub-catchment area connected with it is serious or the runoff in multiple sub-catchment areas converges to it.

(2) The results of submergence level, maximum submergence depth and submergence area obtained by different description methods are similar, and the distribution law of urban rainfall water is the same. With the increase of rainfall intensity, the distribution of water firstly presents the characteristics of distribution along the road. When the submerged water level reaches a certain height, the distribution of water presents the characteristics of priority to submerge the low-lying building area squares on both sides of the road.

(3) Adjust the terrain elevation although can significantly reduce the water area, the most severe significantly reduce the region's largest water depth, but due to the effect of water storage of the lack of low-lying area, it will increase water area. The modification of the underlying surface can significantly reduce the surface runoff, reduce the surface runoff depth, and alleviate the urban surface water problem to a certain extent. Increasing the drainage capacity of rainwater outlet can significantly reduce the amount of water accumulated in the study area, reduce the depth of water accumulated in the study area as a whole, and make the area with serious water accumulated significantly smaller.

KEY WORDS: urban waterlog; water distribution; meticulous; influence factors

目 录

摘要

Abstract

第一章 绪论 7

1.1 研究背景及意义 7

1.2 国内外研究现状 7

1.2.1 城市积水研究进展 7

1.2.2 城市积水影响因素研究进展 8

1.3 研究内容和方法 9

1.3.1 研究内容 9

1.3.2 技术路线 10

第二章 水文模型概述 11

2.1 水文模型简介 11

2.2 水文模型原理 11

2.2.1 地表产流计算 11

2.2.2 下渗 12

2.2.3 管网汇流计算 13

2.2.4 表面积水 13

第三章 研究区域模型建立 13

3.1 研究区域概况 14

3.2 模型建立 14

3.2.1 基础数据采集 15

3.2.2 排水管网概化 16

3.2.3 地表径流模型建立 17

3.2.4 径流模型与管网关联 18

3.2.5 降雨雨型建立 19

3.2.6 结果查看与分析 21

3.3 模型误差分析 22

第四章 研究路段及周边积水分布研究 23

4.1 不同工况方案建立 23

4.2 结果统计与分析 24

4.2.1 不同工况下地表径流流量分布 24

4.2.2 不同工况下节点溢流分布 25

4.3 积水精细化分布描述 27

4.3.1 径流平均深度 28

4.3.2 节点洪流—等体积法 29

4.3.3 地表径流线—等体积法 33

第五章 城市积水分布影响因素研究 36

5.1 城市积水成因分析 36

5.2 局部控制变量模拟 36

5.2.1 地形因素 36

5.2.2 下垫面因素 37

5.2.3 排水系统因素 38

第六章 结论与展望 40

6.1 结论 40

6.2 不足与展望 41

参考文献

致谢

第一章 绪论

1.1 研究背景及意义

随着气候变化和城市化的发展,由于强降雨天气频繁发生、城市下垫面趋向不可渗透性以及城市排水系统老旧堵塞等原因,地表对雨水的滞蓄能力和入渗能力被削弱,排水能力又不足,城市内涝问题越来越突出,内涝积水问题严重影响城市的正常运转[1-3]。近年来全国各大城市遭遇内涝的情况屡见不鲜,比如2017年6月10日江苏省南京市全城大暴雨,黄色、橙色、红色,南京暴雨预警信号三连跳,南京站累计日降水量超过230mm,破了南京1902年有气象记录以来的日累计降水量纪录仅用了10个小时,其中3小时雨量就突破100mm,短时强降水持续长达4个小时。全市当天出现51处积淹水点,秦淮河水位超警戒,全市防汛进入紧急状态,出动6000多人次应急抢险。

国外欧美发达国家从20世纪60年代起开始城市雨洪研究,到20世纪80,90年代已逐步建立了系统的计算理论与技术模型,包括SWMM,STORM,MIKE,InfoWorks CS模型等已满足城市排水、防洪、环境治理的需要[4-13]。近十几年国内学者逐渐开始展开城市内涝积水问题的研究,并逐渐将重点从城市内涝机理转移到了城市积水分布和低影响开发的研究。随着内涝研究的不断进展,小范围内涝积水分布的精细化研究日益成为当下研究热点,而如何利用数值模拟等手段精确得出内涝范围内的积水分布成为难点。

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