城市立交桥洞内涝过程的精细化模拟研究

Research on Refined Simulation of Waterlogging Process in Urban Overpass Tunnels

为科学地指导城市立交桥区的排水防涝改造,降低内涝风险,以深圳市某立交桥为研究对象,构建高分辨率城市内涝模型,采用地表积水实测资料进行模型率定及验证,模拟立交桥洞在雨水口防堵、下凹式绿地以及两者的组合措施改造前后不同降雨情景下的积水情况。结果表明,1)高分辨率城市内涝模型可以实现城市立交积水动态变化过程的准确模拟;2)5年、20年和100年重现期降雨情景下,立交桥洞内涝严重,积水时空变化速率快,当降雨重现期为100年时,最大积水深度和面积分别高达1.52 m和1833 m^(2),积水深度随时间和空间的最大增长速率分别高达0.04 m/min和0.23 m/10 m;3)组合措施的内涝削减效果优于不同改造措施单独使用时的削减效果,100年重现期降雨情景下,单独采用雨水口防堵和绿地下凹措施,仍然存在0.6 m以上深度的积水,而组合措施可使内涝积水深度小于0.5 m,内涝持续时间缩短至30 min内,可有效地缓解桥洞内涝。

To scientifically guide the prevention transformation project of drainage and waterlogging in urban overpass and reduce the risk of waterlogging,a high-resolution urban waterlogging model has been constructed using an overpass in Shenzhen as the research object,and the model was calibrated and verified by using measured surface water data to simulate flow accumulation in the overpass tunnel under different design rainfall before and after the reconstruction of the rainwater outlet anti-blocking,the sunken greenbelt,and a joint measure of these two infrastructures.The results show that 1)the high-resolution urban waterlogging model can accurately simulate the dynamic change process of flow accumulation in urban overpass.2)Under 5-year,20-year,and 100-year return period of rainfall,the overpass tunnel displays serious waterlogging,while the temporal and spatial change rate of flow accumulation is rapid.Under the 100-year return period of rainfall,the maximum accumulated inundation depth and area are as high as 1.52 m and 1833 m^(2),respectively.The maximum growth rate of inundation depth over time and space are as high as 0.04 m/min and 0.23 m/10 m,respectively.3)The waterlogging reduction of combined measure is more efficient than that of various renovation measures used separately.Under the rainfall of 100-year return period,there is still ponding with a depth of over 0.6 m when the measures of rainwater outlet antiblocking or sunken greenbelt are taken alone.With combined measures,the inundation depth could be lower than 0.5 m,and the waterlogging duration could be shortened to less than 30 min,which can effectively alleviate the waterlogging of overpass tunnels.