透水砖铺装地面垫层结构对城市雨水入渗过程的影响

Experimental study on impacts of infiltration treated with porous pavement

为了给透水砖铺装系统综合排水设计提供依据,建立了透水砖铺装地面物理模型,采用4种透水砖铺装结构形式(垫层由不同厚度的无砂混凝土、中砂、砂砾料组合而成),进行了模拟降雨条件下雨水入渗过程试验研究。结果表明:降雨过程中超渗的水流形成表层流,其水分延续入渗使地基土壤水分继续增加;4种处理在模拟降雨1 h,强度59.36 mm/h的情况下产流量均为0,下渗率的大小与垫层透水性程度呈正比,与土壤初始含水率呈反比;在模拟降雨2 h,强度59.36 mm/h的情况下(相当100年一遇2 h降雨量),透水砖铺装地面处理1(垫层结构自上而下为中砂10 cm、砂砾料20 cm),入渗效果最优,此时无地面产流。对于新建居民小区、道路、园林绿化等领域布置综合排水系统,以及那些现有排水系统超载严重,难以进行管网改建或改建代价过高的区域,用透水砖铺装地面取代不透水铺面是减少城市地面淹水频次和涝灾程度的良好途径之一。

Four available porous pavement systems were studied to evaluate their infiltration capabilities of precipitation. The experiments were conducted to simulate different kinds of porous pavements with different sub-base materials in each of catchments, and the discharge volumes from each cell were monitored. The relationship between rainfall intensity, outflow and outflow duration was analyzed. Physical models were established in the laboratory. Because of storage of sub-base, the infiltration forms subsurface flow in the porous concrete block paving and sub-base, which increase infiltration into subgrade after rainfall. The results showed that the runoff coefficients of all treatments were 0 under a rainfall rate of 59.36 mm/h, and the infiltration coefficient of porous pavement was in direct proportion with porosity and inverse proportion with soil moisture. In all treatments, the optimum thickness of the porous pavement is 36-cm that consistes of a 6-cm porous surface course and a 30-cm sub-base （10-cm sands and 20-cm gravel）. When rainfall rate is 59.36 mm/h, and the lasting time is 2 hours, the runoff coefficient of treatment t is 0. In condition of building new residential area, pavements, parks; and rebuilding former overage drainage system too cost, the porous pavement system is a substitute for different imporous surface.