山地城市暴雨洪水中人车失稳风险数值模拟研究

Numerical simulation study on the flood instability risk of people and vehicles in mountainous cities

【目的】为定量分析山地城市暴雨内涝中行人和车辆的失稳风险特征,【方法】以重庆市悦来新城某排水片区为研究区域,构建一二维水文水动力耦合模型,对研究区不同降雨情景下的承灾体暴露性进行了模拟分析,按照最不利原则,从失稳风险范围和失稳持续时间等维度计算分析了典型人车(轿车、SUV、成人、儿童)的失稳风险。【结果】结果显示:降雨重现期越大,承灾体暴露性越高,失稳开始时间越早,持续时间越长,轿车的失稳风险最高,SUV次之,成人最小;四类承灾体在不同重现期下的轻微风险区域占比均最大,且其分布与积水深度较浅(如低于0.15 m)或流速值低于0.4 m/s的区域分布较为相似。【结论】结果表明:失稳风险等级越高的区域,其面临的洪水特征可能越复杂,尤其对于地形起伏多变的山地城市,应根据承灾体的特征进行风险图绘制,并结合降雨预报进行风险预警,提升灾害应急管理的精细化水平。

[Objective]To quantitatively investigate the flood instability risk characteristics of pedestrians and vehicles in mountainous cities,[Methods]a coupled one-and two-hydrological and hydrodynamic model is constructed in Yuelai New City of Chongqing,China.The characteristics of the flood and the exposure of disaster-bearing bodies are simulated and identified under different rainfall scenarios.The flood instability risks of typical pedestrians and vehicles(cars,SUV,adults,children)are computed and investigated from the perspectives of risk areas and durations based on the most unfavor-able principle of flood vulnerability.[Results]Result show that the larger the rainfall return period,the higher the exposure of disaster-bearing bodies,the earlier the instability risks begin and the longer the duration;the flood instability risk of cars is the highest,followed by SUV,and the risk of adults is the lowest.Under different return periods,the proportion of mild risk areas of pedestrians and vehicles is the highest,and their distribution is similar to areas with shallow flood depth(such as below 0.15 m)or flow velocity values below 0.4 m/s.[Conclusion]In the high instability risk areas,the flood charac-teristics tend to be complicated,especially for mountainous cities with large undulating terrains,risk maps should be drawn based on the physical characteristics of the disaster-bearing bodies,and risk warning needs to be carried out combining rain-fall forecasts to promote the emergency management.