天津城市下垫面降雨损失特性试验研究

城市下垫面降雨损失特性是城市水文学研究最为基础也是最重要的内容,以天津市西青区某高校为研究区域,在测量5种典型下垫面入渗及蒸发这2个重要的降雨损失环节基础上,采用情景分析的方法,选取5场代表性降雨事件分析了城市下垫面的降雨损失特性。结果表明:①绿地、沥青混凝土路面、铺砖路面初始入渗率分别为5.28、1.03、0.61 mm/min,而沥青混凝土路面与SBS屋面均不透水。② 绿地、沥青混凝土路面、铺砖路面的降雨损失为入渗损失,蒸发及其他损失可忽略不计,而其他2种不透水性下垫面无入渗损失,蒸发及其他损失不可忽视。③绿地仅在大暴雨事件降雨约50 min后形成超渗产流;沥青混凝土路面在大暴雨与特大暴雨事件中形成超渗产流,产流时间分别为40、10 min;铺砖路面在暴雨、大暴雨、特大暴雨事件中形成超渗产流,产流时间分别为15、20、5 min。④水磨石路面及SBS屋面由于降雨损失较小,在各降雨事件中均迅速产流。

Experimental Study on Rainfall Loss Characteristics of Urban Underlying Surface in Tianjin

The rainfall loss characteristics of urban underlying surface is the most basic and most important content of urban hydrology research. With a university in Xiqing District, Tianjin as the study area, and on the basis of measured infiltration loss and evaporation loss, which are two components of rainfall losses, of five typical underlying surfaces, we investigated the rainfall loss characteristics of urban underlying surface using the scenario analysis on five representative rainfall events. Results manifested that: 1) the initial infiltration rates of green land, asphalt concrete pavement, and brick pavement were 5.28 mm/min, 1.03 mm/min and 0.61 mm/min, respectively, while asphalt concrete pavement and SBS roofing were impermeable to water. 2) The rainfall losses on green land, asphalt concrete pavement, and brick pavement were infiltration losses, whereas evaporation and other losses were negligible; for the other two impervious underlying surfaces, infiltration loss was not observed, while evaporation and other losses could not be ignored. 3) On green land, runoff yield by excessive infiltration was only formed after about 50 min of heavy rainstorm events, 40 min and 10 min after heavy rainstorm and very heavy rainstorm respectively on asphalt concrete pavement, and 15 min, 20 min, and 5 min in rainstorm, heavy rainstorm and very heavy rainstorm events respectively on brick pavement. 4) Rainfall yielded rapidly on Terrazzo pavement and SBS roofing regardless of the rainfall type due to small losses.