雨水径流中悬浮颗粒对透水性混凝土的堵塞规律研究

Study on Physical Clogging of Pervious Concrete by Suspended Solids in Rainwater Runoff

以3种不同孔隙结构混凝土试样为对象,研究雨水径流渗滤过程中透水混凝土内悬浮颗粒的堵塞规律与特征。结果表明,孔隙率为12.7%的小孔隙透水混凝土在实验过程中渗透系数从最初的0.72 cm/s下降至0.05 cm/s,而大孔隙透水混凝土(孔隙率为38.2%)在运行末期仍具有较好的渗透能力,渗透系数仍可达到0.63 cm/s。通过连续运行及计算机断层扫描(X-CT)检测发现,小孔隙透水混凝土截留的悬浮颗粒粒径逐渐减小,说明孔隙内颗粒的持续堆积加剧了透水混凝土的颗粒截留作用,堵塞的颗粒均分布在上层;而大孔隙透水混凝土在运行过程中,穿透的大粒径颗粒占比下降较为有限。因此,在城市路面雨水径流悬浮颗粒粒径级配特征下,选择38.2%孔隙率的透水混凝土对于防止堵塞具有一定的作用。

In this paper,three concrete samples with different pore structures are taken as objects to study the blocking law and characteristics of suspended solids in pervious concrete during rainwater runoff percolation.The results show that the permeability coefficient of small-pore pervious concrete with porosity of 12.7% decreases from 0.72 cm/s to 0.05 cm/s in the experimental process,while the permeability coefficient of large-pore pervious concrete(porosity of 38.2%) still has a good permeability at the end of operation,which can still reach 0.63 cm/s.Through continuous operation and COMPUTED tomography(X-CT) detection,it was found that the particle size of suspended solids intercepted by small pores of pervious concrete decreased gradually,indicating that the continuous accumulation of solids in pores intensified the interception of solids of pervious concrete,and the blocked solids were all distributed in the upper layer.However,during the operation of porous concrete,the proportion of large particle size through the concrete is limited.Therefore,under the characteristics of particle size gradation of suspended solids in urban road surface rainwater runoff,the selection of permeable concrete with porosity of 38.2% plays a certain role in preventing clogging.