渗水井在提高庭院雨水下渗率中的应用

Application of seepage well in improving the infiltration rate of rainwater in courtyard

为减少历史街区中的合流制排水系统的污水溢流量,降低雨污分流改造难度,利用历史庭院下垫层的瓦砾层特点,采用渗水井海绵技术提高地表的雨水下渗率,削减降雨径流.蓄渗性能试验结果表明,瓦砾层平均蓄水率和渗透系数分别为33.52 L·m^-3和13.490 m·d^-1,分别是原状土的7.7倍和245.3倍.通过渗水井将庭院雨水径流汇至瓦砾层可强化下渗,对不同面积庭院的渗水井直径选用方案进行了研究.以汇水面积为120 m2的典型庭院为例,采用直径为1.6 m、蓄水深度为1.1 m的渗水井,能将重现期为3 a、降雨历时为2 h的暴雨所产生的径流削减89.45%.

Based on the characteristics of rubble layer in the underlayer of historical courtyard, sponge technology for seepage wells is used to improve the surface rainfall infiltration rate and reduce rainfall runoff. The method can reduce the sewage overflow of the combined drainage system in historic districts and reduce the difficulty of rainwater and sewage diversion transformation. The experimental results show that the average gravitational water storage rate and average permeability coefficient of the rubble layer are 33.52 L·m^-3 and 13.490 m·d^-1, which are 7.7 and 245.3 times of that in undisturbed soil. Rainwater infiltration is enhanced by converging the runoff from the courtyard to the rubble layer through seepage wells. The diameter selection scheme of seepage wells with different courtyards is summarized. Taking a typical courtyard with catchment area of 120 m2 as an example, the seepage well with diameter of 1.6 m and storage depth of 1.1 m can reduce the runoff by 89.45% caused by heavy rain of recurrence period of 3 a and rainfall duration of 2 h.