城市洪涝下承灾体暴露性及行人失稳风险分析

Analysis on exposure of disaster-bearing bodies and pedestrians’ instability risk under urban waterlogging

为减少城市洪涝灾害造成的人员伤亡和财产损失,以MIKE 21水力学模型为基础,建立武汉市南湖区域雨洪模型。首先,模拟由暴雨强度公式和芝加哥雨型合成的不同重现期、历时120 min、雨峰系数为0.4的降雨洪涝过程;然后,运用地理信息系统(GIS)空间分析技术,从积水深度和降雨时间等维度分析道路、建筑物等承灾体的暴露性;最后,选取20年一遇降雨道路上的积水点,对一定范围内的行人作失稳风险分析。结果表明:区域内承灾体的暴露性与暴雨重现期的变化呈正相关,同时,暴露性的最大值集中在降雨后的60~80 min;降雨后的45~110 min行人会发生长达65 min的失稳风险,需提前发布预警信息,做好防范措施。

In order to reduce casualties and property losses caused by urban floods,a urban flood model of Wuhan south lake was established based on hydraulic model of MIKE 21.Firstly,flood process,which was synthesized by rainstorm intensity formula and Chicago rain pattern,was simulated for designed rainfall with different recurrence periods,rainfall duration of 120 min and a storm peak coefficient of 0.4.Then,exposure of roads,buildings and other disaster-bearing bodies were analyzed from dimensions of rainfall time and water depth by utilizing GIS spatial analysis technology.Lastly,with water accumulation points for rainfall once in 20 years selected,instability risk of pedestrians within a certain range was analyzed.The results show that exposure of disaster-bearing bodies in the region is positively correlated with change of rainstorm recurrence period,and maximum exposure is concentrated in 60-80 min after rainfall.Moreover,pedestrians will have 65 min instability risk after 45-110 min of rain,for which early warning should be made and preventive measures be taken.