摘要
由于全球气候极端化现象加剧,城市洪涝灾害的强度与频率均呈上升趋势。为充分了解城市洪涝灾害的致灾机理,提出行之有效的减灾措施,有必要对典型城镇街区的洪水演进过程进行研究。本文建立了具有典型街区构造的洪水演进物理模型,模型中布设道路、建筑物、人行道、绿化带等设施。基于试验数据定量分析了建筑物密度、绿化带设置等对洪水演进过程带来的影响。得到主要结论如下:(1)溃坝波在模型道路上的运动速度与初始时刻上游水库的水深及道路本身特性有关,建筑物与城市绿化设施的布置对其影响较小;(2)布置绿化带及建筑物减小了过水面积,导致洪涝灾害发生后道路上的水位上升;但增加房屋密度将减少流入街区两侧的水流体积,布设绿化带将增加房屋周边的水流阻力,促使水流沿模型道路演进;(3)建筑物前水深与初始时刻水库内水深近似成正比,但初始水深较大时水流对建筑物的冲击力将远大于初始水深较小的工况。本试验结果可以为数学模型提供翔实的率定资料,并为面临突发洪涝灾害威胁的街区提供设计参照。
Global climate changes and increasingly frequent extreme weather events lead to higher frequency and intensity of urban flooding disasters.In-depth study on flood inundation over typical urban streets becomes essential to understand flooding mechanism and work out effective disaster-mitigating strategy and measures.This study establishes a flood inundation physical model for laboratory experiment to represent a urban street system and its complicated structure,inluding roads,sidewalks,buildings,greenbelts,and other street facilities.From the experimental results,we obtain a quantitative analysis on the effect of building density and greenbelt arrangement on flow inundation process.We come to the conclusions that(i) on the model road,the celerity of dam-break waves depends on initial water depth in the reservoir and road characteristics,while the influences of buildings and greenbelts are insignificant.(ii) Adding greenbelts or buildings to the system reduces the flow cross-sectional area,thereby increasing the flow depth on the road during flood events,but it can reduce the water volume around buildings or increase flow resistance so that more water is concentrated on the road.(iii) Peak depths in front of buildings are roughly proportional to the initial reservoir depth,and a large initial reservoir depth will cause a much stronger impact force on the buildings.This study supplies data for numerical model calibration and helps design urban streets facing outburst flooding threat.
作者
董柏良
夏军强
陈瑾晗
DONG Boliang;XIA Junqiang;CHEN Jinhan(State Key Laboratory of Water Resource and Hydropower Engineering Sciences,Wuhan University,Wuhan 430072)
出处
《水力发电学报》
EI
CSCD
北大核心
2020年第7期99-108,共10页
Journal of Hydroelectric Engineering
基金
国家自然科学基金项目(51725902,41890823)
英国皇家工程院资助项目(UUFRIP\100031)
关键词
城市洪水
洪水演进
城市街区
物理模型
试验研究
urban flood
flood routing
urban streets
physical model
experimental investigation
