地下空间顶板浅层海绵式人工下凹绿地设计及对屋面初期雨水的净化

Design and Purification of Initial Roof Runoff for Shallow Spongy Artificial Sunken Greenbelt on Underground Space Roof

结合海绵城市和地下空间顶板绿化建设,设计了地下空间顶板浅层海绵式人工下凹草地的结构,研究了其吸蓄水特性及对屋面初期雨水的净化作用。采用蛭石、珍珠岩作为吸水剂,与红壤土、腐殖土按一定比例复配为具有海绵式吸水特性的浅层顶板草坪种植基质,具有质轻和持蓄水能力强的优点。结果表明,1 m3复配的人工土壤的饱和吸水量为0.65 m3,持水时间为4~5 d,与昆明市典型红壤土的吸蓄水能力相当,但持水时间是红壤土的2倍,能有效调蓄及储存雨水。同时,对屋面初期雨水中的COD、NH3-N、TN、TP的削减量分别在54.5%~60.3%、46.3%~69.3%、48.5%~61.0%和46.3%~54.0%之间,能对进入的雨水径流具有较好的净化效果。

In this paper, the structure of shallow spongy artificial sunken greenbelt was designed, and its purmcatlon effect on initial roofing rainwater was researched by combining the sponge city development and greening process ion underground space roof construction. Vermiculite and perlite were used as a water absorbent, and mixed with red loam and humus soil by a certain percentage to form shallow lawn planting matrixes with spongy absorbent properties. The mixing composite possessed the advantages of light quality and strong water holding capacity. The experimentresuh showed that the saturated water absorption of 1m^3 artificial composite was 0.65 m^3 and the water retention time was 4-5 d. The water-holding capacity of the composite was similar to but the water-holding duration was twice as much as that of typical red loam in Kunming. Therefore, it can be used to regulate and store rainwater effectively. Meanwhile, the shallow sunken greenbelt of roof has good purification effects on storm runoff. The amounts of COD, NH3-N, TN and TP in initial roofing rainwaterwere reduced by 54.5%-60.3%, 46.3%-69.3%, 48.5%-61.0% and 46.3%-54.0% respectively, compared with those in the rainwater on the roof.