Urban roads are very important for draining excessive rainfall. A routing-enhanced detailed urban stormwater model (REDUS) is developed, and two main roads in the Tsinghua University campus are selected to evaluate how well the road system enhances drainage during typical storms and to quantify the impacts of rainfall type, road longitudinal slope and underground pipe systems. The results show that for the Beijing "721" stormwater event, the roads can drain as much as 50% of the total flooding discharge and the drainage increases dramatically when the pipe network reaches its maximun drainage capacity. The road drainage effectiveness is sensitive to the rainfall characteristics with the drainage correlating well with the maximum 30-min rainfall volume. Branch pipe networks do not continually increase the road drainage effectiveness as the road longitudinal slope increases which indicates that the road flows are closely connected to the flows in the underground pipes. The results will facilitate construction of Sponge City that effectively incorporates the road drainage.
摘要 道路在城市超标雨水排除中有着重要作用。该研究构建了强化汇流过程的精细城市雨洪模型 (REDUS), 以清华园南门主干道和东门主干道为对象, 评价了典型暴雨情景下道路的排涝作用, 以及降雨、道路纵坡和地下管网条件的影响。结果表明：在北京“721”暴雨中, 道路排涝流量占比峰值达到了50%, 在管网达到最大排水能力后, 道路排涝占比显著增大; 道路排涝作用受降雨的影响显著, 与最大30 min累积降雨量之间有较好的相关关系; 对于配有支路管网的道路, 其排涝效果并不随着纵坡坡度单调提升, 表明道路纵坡的影响与地下管网结构有关。该研究结果为海绵城市建设中如何充分考虑道路排涝作用提供了科学依据。