大纵坡城市道路透水边带截留能力试验

道路是城市重要的交通纽带,一旦发生积水内涝,将导致城市交通瘫痪,甚至危及生命财产安全,特别是山地城市道路普遍存在纵坡大、雨水口截留效率低等突出问题,发生积水内涝和马路洪水的风险较高。针对上述问题,提出了利用透水边带提高大纵坡城市道路雨水径流截留效率的方法。在实验室搭建了城市单车道物理试验模型(比例1∶1),采用人工模拟降雨方法,系统研究了不同透水面积比、不同重现期降雨条件下透水边带对雨水径流的截留效率,并与传统道路雨水口截留能力进行了比较。试验结果表明:相同透水面积比条件下,雨水径流截留能力随着重现期的增大而减小;相同重现期条件下,雨水径流截留能力随着透水面积比的增加而增大,在重现期P=5 a时,透水边带面积比从12.5%增加到50%,雨水径流截留率从72.3%增加到79.3%。与传统雨水口截留能力相比,增加透水边带后雨水径流截留能力可提高30%左右。因此,大纵坡城市道路在不影响交通安全的条件下,可根据道路空间布局特征,通过设置透水边带来提高雨水径流的截流效率。

PILOT STUDY ON RUNOFF INTERCEPT RATE OF POROUS BELT BESIDE THE URBAN ROAD WITH LARGE LONGITUDINAL SLOPE

Urban road is an important traffic infrastructure of the city. Once flooding occurs on the urban road, it will lead to an traffic paralysis and even endanger the safety of people and property. Especially in mountainous cities, many roads are with large longitudinal slope, low runoff intercept efficiency of grate inlets, and higher risk of road flooding. For the above problems, a novel method was proposed to improve the stormwater runoff intercept rate of urban roads with large longitudinal slope by using porous belt. A physical experiment model of urban single lane road was built in laboratory. The intercept rates of porous belt under different widths of porous belt and rainfall design return periods were systematically investigated via artificial rainfall process, and the intercept rate of porous belt was compared with that of traditional road grate inlets. The experimental results showed that under the same porous belt width, the stormwater runoff intercept rate decreased with the increase of the return period; under the same design return period, the stormwater runoff intercept rate increased with the increase of porous belt width. When the design return period was five years, the porous belt ratio increased from 12.5% to 50%, and the stormwater runoff intercept rate increased from 72.3% to 79.3%. Compared with the traditional grate inlet, the stormwater runoff intercept capacity could be increased about 30% when the road equipped with porous belt. Therefore, the urban roads with large longitudinal slope could improve the interception efficiency of stormwater runoff by setting porous belt, according to the characteristics of road spatial layout.